Term
| the generalized response to stress |
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Definition
| The brain senses a stressful state from external and internal sensory signals reaching the CNS and integrates them together with stored memory of previous experiences to initiate an appropriate response. The cerebral cortex conveys the integrated information to the voluntary motor system, the limbic system, the hypothalamus and brainstem, to coordinate the somatic, endocrine and autonomic components of a generalized stress response. |
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Term
| adrenal response to stress |
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Definition
| The adrenal gland with its sympathetic (adrenal medulla) and endocrine (adrenal cortex) connections releases the hormones epinephrine and cortisol into the blood. Together they bring about the body’s immediate response to stress (e.g. fight-or-flight) and its longer term adaptation to stress. |
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Term
| cardiovascular response to stress |
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Definition
Increased heart rate, contractile force, conduction velocity
Increased blood pressure
Vasoconstriction in most vascular beds (not the brain), metabolic needs permitting . For example, dilation is seen in contracting muscles, in the heart when cardiac output is increased, and in the skin if the hypothalamus demands the dissipation of heat due to increased muscle activity. |
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Term
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Definition
Sweating
Pallor due to vasoconstriction (unless in flight, for heat dissipation)
Contraction of arrector pili muscles: piloerection (fierce look in animals). |
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Term
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Definition
are set for far vision and a wide field of vision.
Mydriatic pupils (pupillary radial muscle contracts; parasympathetic relaxes pupillary sphincter muscle).
Widened palpebral fissure (contract Muller’s muscle in eyelids)
Flat lens for far vision (inhibit the parasympathetic lens accommodation reflex) |
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Term
| metabolic response to stress |
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Definition
| mobilization of glucose (glycogenolysis; gluconeogenesis) and free fatty acids (lipolysis). |
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Term
| Hypothalamic-Pituatary-Adrenal axis response to stress |
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Definition
| The Hypothalamic-Pituitary-Adrenal axis initiates a longer-term response to stress (adaptation) under the influence of the adrenal cortical hormone, cortisol. Prolonged stress involves continuing release of cortisol, with detrimental consequences. |
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Term
| Is there a generalized parasympathetic response to stress? |
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Definition
| NO, such a generalized response, i.e. a simultaneous discharge of all of the craniosacral parasympathetic nerves at once, would be very dangerous. But this can occur pharmacologically by use of poisonous drugs. One is MUSCARINE, from deadly fly amanita mushrooms, because it stimulates all muscarinic cholinergic receptors. Others are nerve (war) gases and certain pesticides, which inhibit AChE, preventing the rapid hydrolysis of ACh that normally occurs in cholinergic transmission. This prolongs ACh’s actions at all cholinergic receptors, muscarinic [think postganglionic parasympathetic] and nicotinic [think all ganglia and MNJs] and potentially the activation of the entire ANS. |
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Term
| consequences of muscarine poisoning |
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Definition
• The consequences of MUSCARINE poisoning provide a good way to review all of the actions of the POSTGANGLIONIC parasympathetic nerves, where muscarinic receptors activate the target organs of the parasympathetic division. Those muscarinic receptors that are outside of the parasympathetic division are also stimulated by muscarine.
- III nerve: Miotic pupil; contraction of ciliary muscle (near vision)
- VII nerve: Tear secretion; copious secretion from submandibular and sublingual salivary glands
- IX nerve: copious secretion from parotid glands
- X nerve:
o AV node slows or stops the heart; also decreased force of atrial wall contraction
o Lungs: bronchiolar constriction; bronchosecretion (labored breathing)
o GI tract: severe diarrhea from increased motility in the walls and dilation of sphincters; copious secretion of exocrine glands
- Sacral nerves: Urination, defecation, vasodilation in erectile tissue
- Skin: sweating due to cholinergic SYMPATHETIC nerves to skin
- Dilation in vessels where ACh and NO are found, including skeletal muscle arterioles, coronaries, and the endothelium of microvessels. |
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Term
| consequences of muscarine poisoning |
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Definition
The consequences of inhibiting AChE by nerve gases (e.g. sarin) or pesticides (e.g. organophosphates) include all of the symptoms of muscarine poisoning (see above) PLUS additional stimulation of nicotinic receptors in the somatic nervous system and in all ANS ganglia, including sympathetic, parasympathetic, and the adrenal medulla. Thus BOTH divisions of the ANS are stimulated to more or less degree, with an additional release of hormonal EPINEPHRINE. The net effect on individual organs will reflect which division has the more prominent influence (summarized below) and to what extent epinephrine influences the response.
- Muscarinic receptors are more sensitive to ACh than are the ganglionic nicotinic receptors; thus, the postganglionic actions of ACh are especially stimulated by AChE inhibitors, and so are more deadly (stop the heart; constrict bronchioles). This is why atropine (a muscarinic blocker) saves lives.
- Nicotinic receptors in skeletal muscle maintain a contracted state once ACh appears in the NMJ since it cannot be broken down enzymatically. Furthermore, when both agonist and antagonist muscles around the joints contract simultaneously rather than reciprocally, there is much pain.
- Death is due to inability to relax respiratory muscles for exhaling (persistent skeletal muscle contraction), and due to stoppage of the heart (vagus nerve). |
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Term
| In general, parasympathetics exert a more potent influence than sympathetics on ... |
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Definition
| Parasympathetics exert a more potent influence on: control of heart rate; GI and GU motility and secretion; lens accommodation; secretion of aqueous humor, secretion of tears. |
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Term
| In general, sympathetics exert a more potent influence than parasympathetics on ... |
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Definition
Sympathetics have exclusive control of ventricular force and velocity of conduction.
- Sympathetics control all blood vessels, and determine the bulk distribution of blood flow to major vascular beds, according to body needs.
- Sympathetics control the mobilization of energy stores, from carbohydrate, fat and protein stores. |
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Term
| Which autonomic division controls pupil size? |
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Definition
| Both divisions have equal influence on pupil size |
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Term
| ALPHA-1 receptors are usually … |
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Definition
| ALPHA-1 receptors are usually excitatory: they contract smooth muscle and often stimulate secretion. |
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Term
| ALPHA-2 receptors are usually ... |
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Definition
| ALPHA-2 receptors are generally inhibitory on smooth muscle contraction and secretion. |
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Term
| BETA-1 receptors are generally … |
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Definition
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Term
| BETA-2 receptors on smooth muscle cells are generally … |
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Definition
| BETA-2 receptors on smooth muscle cells are generally inhibitory. Beta-2 receptors respond poorly to NE (the transmitter) but are very sensitive to EPINEPHRINE (the hormone). Beta-2 receptors relax smooth muscle, especially important in lung bronchioles and where found in vascular smooth muscle. |
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Term
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Definition
| BETA-3 receptors: an important location is in some adipose tissues, promote lipolysis |
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Term
| M2 muscarinic cholinergic receptors are associated with ... |
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Definition
| with inhibitory actions on the heart, and on sphincters of GU tract (relaxation of smooth muscle). |
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Term
| M3 muscarinic cholinergic receptors are associated with … |
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Definition
| with excitation: they increase motility, promote glandular secretion. |
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Term
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Definition
| Also named "Mecke's cartilage" - Muscles of chewing; Bones: mandible, incus, malleus, maxilla - CN V |
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Term
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Definition
| Also named "Reichert's cartilage" - Muscles of fascial expression; Bones: stapes, styloid, top half of hyoid - CN VII |
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Term
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Definition
| Muscles of swallowing; Bones: lower half of hyoid - CN IX |
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Term
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Definition
| Muscles of swallowing and phonating; Bones: larynx, thyroid cartilage (4), cricoid cartilage (6) - CN X |
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Term
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Definition
| Muscles of swallowing and phonating; Bones: larynx, thyroid cartilage (4), cricoid cartilage (6) - CN X |
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Term
| Origin of pharyngeal gut arches |
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Definition
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Term
| Origin of embryonic pouches |
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| thymus, inferior parathyroid |
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Term
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Definition
| superior parathyroid, U-B body |
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Term
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Definition
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Term
| Why are clefts 2,3, and 4 obliterated? |
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Definition
| By downward growth of Arch 2 and upward growth of arch 4 |
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Term
| Treacher Collins Syndrome |
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Definition
“First Arch syndrome”
AD
Hypoplasia of mandible and maxilla
Malformation of external and middle ears
Gene mutation on 5q32-33.1 |
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Term
| Embryologically, what forms the cervical sinus? |
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Definition
| The remnants of the second, third, and fourth pharyngeal clefts form the cervical sinus - which is normally obliterated. |
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Term
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Definition
- Increase:
1. Heart rate
2. Force of myocardial contraction
3. Velocity of conduction in purkinje system
- Adrenergic receptors, EPI and the transmitter (NE) are equipotent |
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Term
| Sympathetic nerves to heart |
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Definition
| All myocardial tissues innervated by sympathetic nerves from the cervical and upper thoracic chain ganglia |
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Term
| Parasympathetic innervation of heart |
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Definition
- By vagus nerve
- Postganglionic neurons innervate SA and AV nodes and the atria, but NOT ventricles
Vagus has greater influence on SA node than sympathetic |
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Term
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Definition
Decrease:
1. Heart rate
2. Conduction velocity
3. Atrial force of contraction |
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Term
| Sympathetic innervation of vessels |
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Definition
| - All vessels with smooth muscle layer outside brain have sympathetic innervation |
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Term
| Vasoconstriction mediation |
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Definition
- Alpha-1 adrenergic receptors on vascular smooth muscle mediate vasoconstriction
- all vascular smooth muscle contains alpha-1 adrenergic receptors in greater or lesser density |
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Term
| Beta-2 adrenergic receptors |
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Definition
| - on some vascular smooth muscle (esp skeletal muscle and coronary arteries)vasodilae in response to EPI in blood (transmitter NE has much lower potency at Beta-2 receptors |
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Term
| Parasympathetic innervation of blood vessels |
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Definition
- none, except in erectile tissue blood vessels in genitalia
- receive parasympathetic, cholinergic nerves from sacral spinal cord
- ACh dilates them at muscarinic receptors by synthesis of NO |
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Term
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Definition
- partial constriction of blood vessels at rest due to a low persistent firing rate of sympathetic nerves acting on alpha-1 receptors in vascular smooth muscle
- baroreceptor reflex center in medulla responsible for resting tone
- set-point of mean arterial pressure (monitored in aortic and carotid sinuses) determines firing rate of sympathetic constrictor nerves, increasing rate to vasoconstrict or decreasing to cause passive vasodilation |
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Term
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Definition
- seen where cholinergic nerves (erectile tissue) or ACh formed in vascular endothelial cells lead to NO formation and vasodilation
- also seen where beta-2 adrenergic receptors are (skeletal m. arterioles, and heart's coronary arterioles)found ina ddition to lots of alpha-1 constrictors in all arterioles |
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Term
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Definition
| - serves as moment-to-moment regulator of blood pressure to maintain a steady state, meet changing needs of body and guarantee sufficient blood flow to brain |
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Term
| afferent limb of baroreceptor reflex |
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Definition
- in the carotid and aortic sinuses which detect pressuree
- 9th and 10th cranial nerves contain these afferent, sensory, "pressoreceptors" or "baroreceptors" |
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Term
| Efferent limb of baroreceptor reflex |
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Definition
- includes sympathetics innervating heart, all arterioles, and small veins (except in CNS)
- also includes parasympathetic motor branch of the vagus nerve innervating the nodal tissue and atrial muscle of the heart |
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Term
| baroreceptor reflex center |
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Definition
- in medulla oblongata (part of cardiovascular control center)
- set point determines BP level to maintain
- rise in arterial pressure results in decreased sympathetic activity and increased vagal firing, thereby lowering both HR and total peripheral resistance (and vice versa) |
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Term
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Definition
1. splanchnic
2. skin
3. skeletal muscle mass
- macro distribution of blood flow to these is regulated by cardiovascular center through sympathetic nerves
- micro distribution at tissue level is regulated by local production of vasodilating chemicals in actively metabolizing tissues and by intrinsic mechanims built in to some organs' regulation |
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Term
| Sympathetic nervous system and exercise |
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Definition
- increases cardiac output by increasing:
1. Heart rate
2. force of contraction and conduction velocity
3. peripheral vascular resistance by generalized vasoconstriction especially in splanchnic organs |
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Term
| Metabolic products released by contracting muscles |
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Definition
- act as potent local vasodilators
- incldue: acidic breakdown of glucose, purines from breakdown of ATP, CO2 ets |
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Term
| what drives massive increase in O2 uptake during exercise |
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Definition
| - high production of CO2 by muscles |
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Term
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Definition
| - refers to blood vessels of abdominal and pelvic visceral organs |
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Term
| Splanchnic bed and sympathetic regulation |
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Definition
- makes this primary souce of blood volume for redistributing to more active organs when needed
- under constant regulation by the baroreceptor reglex and by higher centers when appropriate
- when splanchnic organ are active (like in gut during digestion, motility, and secretion) vasodilation occurs locally, controlled by ANS and intrinsic plexus reflexes |
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Term
| Skeletal muscle blood vessels |
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Definition
- dilate only when active due primarily to metabolites produced during contraction
- intrinsic (local) regulation is key!
- also nervous regulation (sparse): mostly noradrenergic vasoconstrictors (under baroreceptor reflex control acting on alpha-1 receptors so resting m. has sympathetic tone (partial vasoconstriction in arterioles and veins)
- cholinergic dilators (small population of sympathetic nerves to muscle arterioles)upstream of noradrenergic nerves function to bring extra blood flow to m. in anticipation of contraction (ACh results in NO production)
- Skeletal muscle arteriolar smooth muscle has beta-2 adrenergic receptors (dilate) and alpha-1 (constrict)
- epi is stimulator of beta-2, but if epi rise is too high then alpha also stimulated and since they are more numerous you end up getting constriction
- metabolites from muscle contraction major cause of vasodilation in the arterioles (supercedes the baroreceptor driven constriction) |
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Term
| Hypothalamus and skeletal muscle arteriole control |
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Definition
- overrides all ongoing control of skeletal muscle blood vessels when faced with severe hemorrhage or other significant loss of blood volume and pressure
- metabolizes all vascular beds, including muscle (but not brain) by generalized sympathetic vasoconstriction to ensure blood flow to brain and heart |
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Term
| Kidney blood vessel innervation |
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Definition
- ANS has limited role in urine formation by nephron
- sympathetic important for regulating renal blood flow, and helps with renin secretion
- Intrinsic controls within nephron with some help of ANS ensure urine formation does not cease even with vasoconstriction (by sympathetics) |
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Term
| Sympathetic nerves to kidney |
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Definition
- vasoconstrictors, acting at alpha-q adrenergic receptors
- during general sympathetic discharge, including exercise, vasoconstriction in splanchnic organs mobilizes a major part of the total blood flow needed for redistribution and urine formation rate goes down
- sympathetics innfervate afferent and efferent arterioles of glomerulus
- both do vasoconstriction as part of splanchnic bed under control by cardio center's baroreceptor reflex mechanism |
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Term
| Afferent and efferent arterioles in the kidneys |
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Definition
- efferent have narrower diameter creating more resistance
- the resistance ensures a hydrostatic force in glomerular capillaries that is higher than in ordinary capillaries allowing for ULTRAfiltration of blood
- glomerular blood flow and filtration rate in both is reduced when sympathetic discharge occurs (Renin is released in response to reduced renal blood flow and filtration, from the juxtaglomerular apparatus), intrinsic mechanisms keep kidneys running |
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Term
| instrinsic release of renin |
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Definition
| - renin leads to angiotensin II |
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Term
| Angiotensin II in response to low blood flow (by intrinsic mechanisms) |
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Definition
- from renin
- constricts efferent arteriole more than afferent maintaining some hydrostatic force in glomerular capillaries
- stimulates renal absorption of Na and water (expands blood volume)
- raises total peripheral resistance, both of which raise mean arterial bp and help pefuse kidneys |
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Term
| Symopathetic innervation to JGA and renin |
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Definition
- sympathetics also stimulate renin secretion
- receptor is beta-1
- hypothalamically regulated secretion of renin is one way for hypothalamus to maintain bp, blood volume, salt and water balance |
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Term
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Definition
- sympathetic (chain ganglia) controls blood vessels, sweat glands, and pilomotor muscles (arrector pili) in skin
- Sympathetic noradrenergic vasoconstrictor nerves innervate all. Vasodilation occurs passively by decreasing firing rate in vasoconstrictor nerves
- no parasympathetic |
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Term
| Skin blood vessel innervation |
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Definition
baroreceptor reflex center controls skin blood
- hypothalamus controls skin blood vessels during homeostatic regulation of body temp. heat retention center and dissipation center reside in separate nuclei in hypothalamus
- emotions in limbic system regulate skin blood vessels during various emotional states
- depending on emotion, pathways from diff limbic areas find their way to hypothalamus and down to selected sympathetic chain ganglia |
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Term
| Heat control through skin vasculature and innervation |
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Definition
Cold environment: sympathetic nerves shunt blood to deep blood vessel plexus by increasing firing rate in both deep and superficial vascular beds.
- prolonged exposure to cold contricts all skin vessels and can result in death of skin tissue (gangrene) from ischemia
Hot environment: superficial perfusion for heat dissipation by decreasing sympathetic firing (passive dilation) heat loast by RADIATION and CONVECTION |
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Term
| Eccrine sweat gland and innervation (general) |
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Definition
- secrete watery sweat to dissipate heat by EVAPORATION
- distributed universally over skin
- stimulated by cholinergic neurons in sympathetic chain ganglia (muscarinin cholinergic receptor) |
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Term
| Sweating when hot (autonomics) |
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Definition
- heat dissipation center in anterior hypothalamus stimulates secretion of sweat while also vasodilating skin
- skin appears flushed and sweaty
- SUDOMOTOR nerves (cholinergic) and VASOMOTOR nerves (noradrenergic) travel together in sympathetics exiting from paravertebral trunk ganglia |
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Term
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Definition
- "adrenergic" sweating
- alpha adrenergic receptors appear on sweat gland cells too
- not neuronally stimulated but respond to epi in blood released when fear or F-F triggers a limbically-driven general sympathetic discharge
- the discharge also results in neuronally triggered vasoconstriction and sweating
- results in cold (blue) and clammy appearance |
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Term
| Pilomotor muscles (arrector pili) innervation |
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Definition
- smooth muscle around hair follicles is innervated by sympathetic nerves (alpha-1)
- contraction raises hairs for insulation to stem loss of body heat
- under control by hypothalamus
- important for furry animals, but for us it just causes goose bumps (also seen in limbically driven fright with cold sweat. |
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Term
| Change in core temp required for hypothalamic response |
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Definition
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Term
| Hypothalamic response to fall in core temperature |
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Definition
1. sympathetics shunt skin blood flow
2. arrector pili contract to insulate
3. sympathetics trigger lipolysis in fat stores via beta-1 and beta-3 adrenergic receptors to increase heat production when fatty acids are metabolized
4. Shivering - involuntary contraction of voluntary muscles. This increases heat production and is driven involuntarily by hypothalamus when body temp falls
5. long term response by hypo is to increase thyroid hormone secretion to raise metabolic rate (increase heat production) |
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Term
| Hypothalamic response to a rise in body temperature |
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Definition
1. sweat glands stimulated to dissipate heat
2. skin blood flow shunted to superficial layers of skin for radiation and convection
3. accompanied by desire to drink fluids and decrease muscle activity |
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Term
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Definition
- dual innervation of bronchiolar smooth msucle, ANS regulation of airways can by overridden by locally released agents and inflammatory cytokines
1. sympathetics from upper thoracic chain ganglia dilate bronchioles via Beta-2 receptors increasing airflow in lungs
2. parasympathetics of vagus CONTRACR bronchiolar smooth muscle via muscarinic receptors restricting airflow in lungs
- gland cells within bronchi secrete mucus and fluid. Innervated by vagus nerve which promotes secretion (muscarinic receptors) |
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Term
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Definition
1. pupil diameter
2. the refractive power of crystalline lens
3. formation and drainage of aqueous humor
4. blood flow
5. tear secretion |
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Term
| Oculomotor complex and eye control |
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Definition
- in midbrain near oculomotor cranial nerve nucleus
Controls:
1. pupillary reflex: receives stimuli of light from retina through optic nerve and then adjusts pupil size and lens for clear vision
2. lens accomodation reflex and associated eye movements: coordinates symp and parasymp outflow to autonomic structures in ant. portion of eye (iris and ciliary body), and to extraocular muscles to point cornea in direction of image to be viewed |
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Term
| Parasympathetic innervation of eye |
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Definition
- cranial nerve innervates pupillary sphincter muscle of iris and epithelium and ciliaris muscle of ciliary body
- tear glands OUTSIDE orbit are innervated by facial nerve (VII) |
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Term
| Sympathetic innervation of eye |
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Definition
- from 2 superior cervical ganglia at top of paravertebral chains
- innervate pupillary radial muscle, all blood vessels within and outside eye, and muller's muscle (superior tarsal muscle) in eyelids |
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Term
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Definition
| - Iris may appear to be one smooth muscle containing organ, part of pigmen ted "uveal tissues" underlying the sclera, but it actually functions as if it were 2 separate organs, each regulated simultaneously and reciprocally by oculomotor complex to acieve pupil diameter appropriate to lighting |
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Term
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Definition
- inner circularly oriented smooth muscle bundle
- innervated by parasympathetic nerve III
- when contracts it narrows the pupil diameter |
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Term
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Definition
- radially oriented smooth muscle bundle
- innervated by sympathetic nerves from superior cervical ganglion? (SCG)
- when contracts it widens pupil diameter |
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Term
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Definition
- wide pupil
- due to contraction of radial pupillary muscle by sympathetic nerves at same time that parasympathetics relax sphincter pupillary muscle by decreasing firing rate of oculomotor nerve (III) |
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Term
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Definition
- narrow pupil
- due to contraction of sphincter pupillary muscle at same time that sympathetic decrease firing rate to radial pupillary muscle |
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Term
| Secretion of aqueous humor |
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Definition
- epithelium of ciliary body, also part of "uveal" tissues secretes aqueous humor which circulates in eyeball and drains into canal of schlemm via trabecular network in "angle of eye"
- parasympathetic of oculomotor nerve promotes secretion (although beta-1 receptors in ciliary epithelium inhibit secretion when stimulated by EPI |
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Term
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Definition
| - intraocular pressure is abnormally increased as a result of an imbalance in the rate of secretion and rate of drainage of aqueous humor |
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Term
| Lens accomodation reflex innervation |
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Definition
- mediated entirely by parasympathetic oculomotor nerve at muscarinic receptors in ciliaris muscle
- zonular fibers actually do the active part |
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Term
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Definition
- attach outer rim of lens capsule to ciliary body anchoring lens firmly within aqueous milieu
- tension exerted by these fibers determines whether lens will be flatter (less refractive power as needed for far vision) or fat (more refractive power for near vision
- oculomotor nerve controls lens thickness by contracting for fat and relaxing for flat sphincter-like ciliaris muscle
- elasticity of lense capsule is responsible for fattening lens when tension on suspensory ligaments is reduced |
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Term
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Definition
- ciliaris m. is relazed so each smooth muscle cell is elongated and skinny pulling on zonular fivers
- more tension, flat lens, lower reflective power |
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Term
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Definition
- ciliaris contracts
- the muscle cells fatter, decreasing tension in zonular fibers
- natural elasticity of lens gives it a rounder shape
- more refractive power |
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Term
| What causes lens accomodation reflex? |
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Definition
- when an object up-close projects blurry image on retina cerebral cortex (striate cortex) detects lack of acuity and signals oculomotor to initiate reflex:
a. contraction of ciliaris m. by parasymps fattens lens to give refractive power
- bends incoming light rays emitted from close-up object allowing image to be focused more sharply on retina
b. contraction of iris sphincter m. by parasymps of oculomotor decreases pupil size, narrows visual field and focuses image on fovea for greatest acuity (highest density of visual receptors in retina)and only fovea has color cones
- rods (black and white) are in all parts of retina
c. somatic motor nerves to medial recuts m. turn both eyeballs inward to focus on object close up |
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Term
| Lacrimal glands and innervation |
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Definition
- controlle by division of ANS
- parasympathetics are main secretory nerves (pterygopalatine ganglion)
- secrete watery tears in response to emotional states, dryness, irritation, or injury
- special glands behind eyelashes also secrete gel-like tear film which resists evaporation and keeps conjunctiva and cornea moist |
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Term
|
Definition
- contain band of smooth muscle (superior tarsal (Muller's m.) m. that is innervated by sympathetic nerves from SCG
- contraction (alpha-1) raises eyelids, widening palpebral fissure for wide filed of vision |
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Term
|
Definition
- partial or total sympathetic denervation of eye
- usually unilateral often due to damage to sup. cervical ganglion or its nerve trunk in neck
Symptoms:
1. miosis on affected side
2. ptosis (lid lag) on affected side
3. Flushed facial skin (vasodilation) on affected side
4. failure to sweat on affected side
5. Supersensitivity to low concentrations of epi in blood
- wider dilation of pupil on affected side compared with normal eye, relief of ptosis in affected eye; less flushing on affected side. no supersensitivity of facial sweat gland secretion
- innervation is cholinergic
- no effect on parasymp on affected side (lens accomodation, salivary secretion, aqueous humor formation, lacrimation) |
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Term
| Autonomic control of salivary secretion |
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Definition
1. parasympathetic: 7th and 9th cranial emanating from 2 salivator centers in brain stem which corrdinate with reflex secretion
- parasympathetics stimulate secretion of watery fluid and digestive enzymes via muscarinic receptors
2. sympathetic postganglionics from sup. cervical ganglion stimulate mucous glands via alpha-1 adrenergic receptors, and innervate blood vessels |
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Term
| Autonomic innervation of walls and glands of GI tract |
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Definition
1. Parasympathetic: vagus innervates from mid-esophagus through mid-colon
- sacral outflow innervates mid-colon to internal anal sphincter
- simulate motility and secretion via muscarinic receptors on smooth muscle cells, gland cells, and neurons of intrinsic plexuses
2. Sympathetic is from collateral ganglia: inhibit motility and secretion at alpha-2 and beta-2 receptors on smooth muscle, gland cells, and cell in intrinsic plexuses
- alpha-1 receptors promote secretion in mucous glands |
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Term
| Sphincter (of GI tract) innervation |
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Definition
1. Parasympathetics: relax (muscarinic), imporant for motility
2. Symapthetics: contract (alpha-1 receptors) inhibit motility function |
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Term
| Innervation of blood vessels in GI tract |
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Definition
- sympathetic from collateral ganglia constricts vasculature at alpha-1 receptors, under tonic reg y baroreceptors
- this blood supply (major part of splanchnic ved) is primary source available to body for rapid redistribution of blood flow when need arises
-vasoconstrictor nerves are an important efferent arm of baroreceptor reflex arc |
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Term
| Defecation and micturition reflexes |
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Definition
- sympathetic nerves from lumbar spinal cord inhibit (relax walls, contract sphincters)
- upon signal from mechanoreceptors detecting stretch on filling of bladder or rectum CNS either postpones reflex or initiates sympathetic inhibition and allowing parasympathetic division to execute the reflex from its center in the sacral spinal cord
- voluntary initiation of these after potty training - absent in early development and in spinal crod injuries |
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Term
|
Definition
1. stretch receptors in lower colon detect filling. Higher centers respond to initiate the reflex (or postpone it). When initiated, sacral cord coordinates the reflex
2. somatic nerves voluntarily relax the external anal sphincter, a skeletal muscle; (nicotinic cholinergic receptors) permitting a parasympathetic reflex
3. Parasymps contract rectal and sigmoid colon walls and relax internal anal sphincter, allowing emptying of lower bowel. Receptors in walls and sphincter are in all cases muscarinic, each signaling via diff G proteins, the one in the walls promoting motility. the one in the internal anal sphincter promoting relaxation
4. Inhibitory ingluence of symp is mediated by beta-2 receptors in the sigmoid and rectal walls and apha-1 receptors promote contraction in internal anal sphincter by generating diff second messengers |
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Term
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Definition
- reflex center also in sacral spinal cord, stretch receptors in walls of bladder detect stretch and elicit desire to empty bladder
-Parasympathetic division here too is primary mediator of miturition reflex
1. symp is inhibitory. Symp from lumbar cord contract trigone sphincter (alpha-1. and relax detrusor muscle (beta-2)
2. afferents detect stretch on filling. Higher centers initiate reflex or postpone it
3. somatic nerves relax external sphincter, a somatic muscle (nicotinic receptors)
4. parasymp sacral nerves contract the detrusor muscle and relax internal sphincter - the trigone region of the muscle wall- and urine is expelled
- receptors at detrusorand trigone region are muscarinic cholinergic |
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Term
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Definition
- parasympathetic, reflex dilation of blood vessels in erectile tissue in 3 cords within penis, coordiated by a center in the sacral spinal cord
- cholinergic parasymps stimulate release of NO = engorgement of erectile tissues with blood
- engorgement compresses superficial veins surrounding cords, maintaining the erection by a positive feedback mechanism until stimulus of dilation ceases with initiation of the ejaculation (sympathetic) reflex
Recap:
1. sexual stimulation
2. parasymp neuros release NO causing dilation of small arteries to penis and veins are compressed reducing blood flow away from penis
3. blood accumulates in vascular spaces within erectile tissues of penis
4. penis swells and becomes erect |
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Term
| Ejaculation Reflex in males |
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Definition
- symp nerves (alpha-1 receptors) mediate contraction of ducts and gland capsules to convey sperm from epididymus to vas deferents and ejaculatory duct where secretions from 3 accessory glands are added to seminal fluid
- during ejac reflex the trigone sphincter of bladder contracts (alpha-1) to prevent entry semen into urinary bladder. all coordinated by sympathetic center
Recap:
1. intense sexual stim
2. symp impulses contract smooth muscle
3. a. peristaltic contractions in testicular ducts, epididymides, ductus deferentia, and ejac ducts
b. rhythmic contractions in erectile columns of penis
c. rhythmic contractions in bulbourethral glands, prostate gland, and seminal vesicles
4. Emission - semen moves into urethra
5. Ejaculation - semen is forcefully expelled from urethra |
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Term
| Erection reflex in females |
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Definition
| - mediated by parasympathetic division from a center in sacral cord. Efferent cholinergic nerves dilate erectile tissues in clitoris and labia minora |
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Term
| Ejaculation reflex in females |
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Definition
- occurs during climax or orgasmic response
- mediated by a center in lumbar cord
- consists of contractions of smooth muscle in vagina, uterus and viducts, and rhythmic contractions of pelvic (somatic) muscles |
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Term
| Liver gylcogeolysis and glucoeogenesis |
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Definition
| - epi acting on beta-2 and alpha-1 receptors in liver cells raises blood glucose by breakdown of glycogen and generating glucose from amino acids; epi is mobilizer of energy reserves in form of glucose |
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Term
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Definition
- mobilization of energy reserves as free fatty acids from adipose tissue stores
- numerous adrenergic receptors invoked: beta-1 and beta-3
- some adipose stores innervated by symp, others non-ionnervated and respond only to hormonal signals like epi |
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Term
| Insulin release inhibition |
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Definition
- via alpha-2 receptors on pancreatic beta islets cells
- this prevents insulin from storing blood glucose as glycogen and thus keeps glucose available as a metabolic substrate, especially for brain in F-F, exercise, etc.. |
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Term
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Definition
- in juxtaglomerular apparatus region of the kidney by beta-1 receptors, to raise bp and promote Na and water retention
- renin converts angiotensinogen i plasma to angiotensin-1, which when converted to II by a converting enzyme, is body's most potent pressor agent |
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