Understand how the membrane potential of a neuron is created and maintained. Know the difference between passive and gated ion channels

  ·         Created by uneven distribution

·      High Na⁺ outside, high K⁺ inside, negative charged proteins outside balanced by K⁺ channels allow flowing out to gradients--> extra positive outside negative charged membrane. Its maintained by the Sodium-Potassium pump

·         Passive ion channels-always open, contribute to resting membrane and alter how it responds to changes in the flow of ions

·         Active ion channels-open in response to a stimulus by chemical, electrical or mechanical  

Understand how graded potentials summate to produce action potentials

• Summation: adding toether of graded potentials (changes in membrane potential) at the trigger zone, upon reaching threshold, triggers action potential
• Spartial summation: 2 APs reach axon hillock from different spaces (different dendrite)
• Temporal summation: 2 APs reach axon hillock at different times, but from the same space (same dendrite)

Review the steps in synaptic transmission

1.      Action potentials arriving at the presynaptic terminal causes voltage gated Ca2+ channels to open

2.      Ca2+ diffuse into the cell and cause synaptic vesicles to release neurotransmitter molecules

3.      Neurotransmitter molecules diffuse from the presynaptic terminal across the synaptic clef

4.      Neurotransmitter molecules combine with their receptor sites and causes ligand gated Na+ channels to open. Na+ diffuse into the cell or out of the cell and cause a change in membrane potential

Review the different types of graded potentials

• Receptor Potentials: graded potentials produced in gustatory receptors, sensory receptors, and hair cells; AP propagate toward CNS if threshold is reached
• Generatopr Potentials: summate until reaching threshold to fire APs; can either be postsynpatic potentials or potentials of the sensory neurons of peripheral receptora
• Postsynpatic Potential: ESPS or IPSP; excitability of postsynpatic cell can change, ESPS increases likelihood of firing APs and ISPS decreases it
• Peripheral Receptors: Sensory neruons fire APs when stimulation is high enough; enough generator potentials summate to produce APs

Briefly review the pathways of information processing in the gustatory and olfactory

senses. How are these two senses similar and how are they different?

• Olfaction
• Axons of the olfactory neruons in the olfactory epithelium project through foramina in the cribriform plate to the olfactory bulb
• Axons of the nuerons in the olfactory bulb project through the olfactory tract to the olfactory cortex or secondary olfactory areas
• Axons from the intermediate olfacotry area project along the olfactory tract to the olfactory bulb. Action potentials carried by those axons modulate the activity of neruons in the olfactory bulb
• Gustation
• Axons of sensory neruons, which synpase with taste receptors, pass through crainal nerve VII, IX, and X and through the ganglion of each nerve
• The axons enter the brainstem and synpase in the nucleus of the tractus solitarius
• Axons from the nuclues of the tractus solitarius synpase in the thalamus
• Axons from the thalamus terminate in the taste area of the cortex
• They are the same because both are required  to perceive flavor and have strong and direct connection to our most basic needs
• They are different because the olfaction pathway doesn't travel through the thalamus, have different chemoreceptors and have different effects on behavior

Review the layers of the eye and the functions of the major structures in each layer

·         Fibrous tunica

o   The sclera helps maintain the shape of the eyeball, protects its internal structures and provides an attachment point for the muscles that move it

o   The cornea permits light to enter the eye and bends or refracts that light

·         Vascular tunica

o   The ciliary muscles function as a sphincter and contractions of these muscles can change the shape of the lens

o   The iris regulates how much light can enter by controlling the pupil

·         Nervous tunica

o   The retina captures light and converts them into electrical impulses  

Trace the path of visual information from the light entering the eye to reaching the

visual cortex

·         Light passes through and refracts in the cornea

·         The cornea refracts light in the pupil, which goes through the lens

·         The lens process photoreceptors that undergo retinal processing

·         It travels through the optic nerve to the optic tract synapse at the thalamus and goes through the visual cortex

·         Sounds enter the ear and hits the tympanic membrane which vibrates through the ossicles to the oval window

·        The perilymph and endolymph transfer the sounds to the organ of Corti to cranial nerve VIII

·         It travels through the medulla and midbrain to the thalamus and into the auditory cortex

How does the structure of the cochlear duct and the organ of Corti help us pick up

different frequencies of sound

Explain the difference between static and dynamic equilibrium. Which structures of

the inner ear are involved in each

·         Static equilibrium- evaluates the position of the head relative to gravity and detect linear and acceleration and deceleration 

o   The utricle and saccule

·         Dynamic equilibrium- evaluates movement of the head

o   The semicircular canals, ampulla, and the cupula

Review the layers of the skin and understand how the epidermis regenerates itself

·         Dermis- is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain

·         Epidermis- contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis

·         The stratum basale and stratum spinosum of the epidermis have the capability of undergoing mitosis and forming more cells

Understand the similarities in the cellular structure of the epidermis, the hair, and the

nails

• Consists of epithelium tissue and kertain; mostly organized into strata
• Skin: contains 4-5 layers
• Hair: hair and internal epithelial root sheat formed by matrix cells that differentiate, becomes keratined and die
• Nails: cutile made of stratum corneum, nail composed of dead stratum corneum layers contaning a very hard type of kertain

·         Sebaceous Glands produce sebum which prevents drying and protects against some bacteria

·         Sweat Glands have two types eccrine which produce sweat which evaporates and cools the body and apocrine glands which causes body odor

Review the different types of sensory receptors found in the skin, and their different

functions

·         The mechanoreceptors of the skin are the Meissner's corpuscles which respond to light touch, the Pacinian corpuscles deeper in the dermis and respond to pressure, and the Merkel's disks respond to light touch. The nociceptors are pain receptors that recognize hot, cold, and pain

Review the different types of hormones (lipid vs. water soluble) and understand how

their cellular mechanisms may differ

·         Lipid-Soluble Hormones

o   Are non-polar and include steroid hormones, TH, and fatty acid derivative hormones

·         Water-Soluble Hormones

o   Are polar molecules and include proteins, peptide, and amino acid derivatives  hormones

·         TSH- stimulates synthesis and secretion of TH  

·         GH- stimulates growth in most tissues and play a role in height and metabolism

·         ACTH- increases the secretion of hormones from the adrenal cortex

·         LH/FSH- stimulate the production of gametes and control the production of reproductive hormones

·         Prolactin- stimulates milk production

·         Oxytocin-smooth muscle contraction for urteres and breast

·         ADH- retains water in blood by reducing urine volume and constricts blood vessels

·         TH- growth, maturation, increased metabolism

·         Calcitonin- reduce calcium levels in body fluids

·         PTH- increase blood calcium levels

·         Aldosterone- raises blood pressure through increase Na+ and water reabsorption

·         Cortisol- increased protein and fat breakdown, glucose production, decrease inflammation

·         Androgens- female: development of secondary sex characteristics

·         Epinephrine/ Norepinephrine- increase cardiac output, blood flow to skeletal and muscles and heart, vasoconstriction, release of fatty acids into blood, and prepare for physical activity and stress

·         Glucagon-break down glycogen and increase blood glucose

·         Insulin- lower blood glucose

·         Testosterone-spermatogenesis, development and maintenance of reproductive organs and develop of secondary sex characteristics

·         Estrogen- endometrial proliferation and development of secondary sex characteristics

·         Progesterone- hypertrophy if endometrial cells, maintains pregnancy, and development of secondary sex characteristics 

Review the hormonal control of blood glucose level and blood calcium level. What

are the major hormones involved

·         Look at the chart

·         Blood Glucose hormones involved: Insulin (increase), Glucagon (decrease)

·         Blood Calcium hormones involved: Caltitonin (increase), PTH (decrease)  

Be sure that you understand the hormonal regulation of blood pressure. We have

been over this again and again as we went through different systems

·         Look at the chart

Review the stress response, and understand how it involves both neural and

endocrine components. How does it integrate with the hormonal control of blood

flow

·         Look at Chart

·         General Adaptation Syndrome

1.      Fight or Flight

§  Neural stimulation from sympathetic nervous and endocrine stimulation via release of epinephrine and norepinephrine from system helps deals with short term stress

2.      Resistance reaction

§  Endocrine stimulation via adrenal cortex for long term resistance to stress; aldosterone keeps blood pressure high than normal, cortisol keeps glucose levels in blood high and androgens stimulate muscle mass and cell growth

§  If the resistance reaction continues, exhaustion which has negative health  impacts mainly because of suppression of immune system by glucocorticoids

Make sure you understand the process of meiosis and how it differs from mitosis

·         Mitosis: diploid cells divide to make 2 more identical diploid cells

·         Meiosis: diploid cells divide to make up two 4 haploid cells (gametes)

Review the endocrine regulation of spermatogenesis in the male and oogenesis in the

female

·         Testosterone stimulates spermatogensis

·         FSH and LH stimulates oogenesis 

·         Ovarian Cycle

o   FSH initiates the development of the primary follicle

o   The follicle secrete a substance that inhibits the development of other follicles

o   LH stimulates ovulation and completion of the first meiotic division by the primary ooctye

o   The LH surge stimulates the formation of the corpus luteum

·         Uterine Cycle

o   Menses (day 1 to day 4 or 5). The spiral arteries constrict and endometrial cells die

o   Proliferative phase (day 5 4o 14). Epithelial cells multiply and form glands

o   Secretory phase (day 15 to 28). The endometrium becomes thicker, and the endometrial glands secrete

o   Estrogen stimulates proliferation of the endometrium  

1.      Many sperm cells attach to the corona radiata of a secondary ooctye

2.      Sperm cells attach to zona pellucida  glycoprotein (ZP3) receptors on the zona pellucida and acrosomal enzymes digest through the zona pellucida

3.      The head of one sperm cell penetrates the zona pellucida, attaches to aplha-6-beta1 integrins on the ooctye plasma membrane, and penetrates the oocyte plasma membrane to enter the oocytes cytoplasm. Changes in the zona pellucida (moving away from the oocyte) form a space and prevent additional sperm cells from entering the ooctye

4.      In response to the entry of the contents of the sperm head into the ooctye the ooctye nucleus moves to one side where it completes the second meiotic division and gives off a second polar body. When the second meiosis is complete the oocyte nucleus now called the female pronucleus moves back towards the center of the ooctye

5.      The contents of the sperm head enlarge and becomes the male pronucleus

6.      The 2 pronuclei fuse to form a single nucleus. Fertilization is complete and a zygote results  

Understand how the various components of the ECG correlate to the events

occurring within the chambers of the heart

·         P wave – atrial depolarization (contraction)

·         QRS complex – ventricular depolarization (contraction)

·         T wave – ventricular repolarization (relaxation)

·         *Atrial repolarization occurs during QRS complex, not shown

·         PQ (or PR) interval – length of time required for AP's from SA node to reach ventricle

·         QT interval – length of time required for ventricles to contract and begin to relax

Review the cardiac cycle, including volume and pressure changes

Review the regulation of cardiac output. Be sure to know the major influences on

stroke volume and heart rate

·         Arteries

o   Structure: thick walls with a small lumen; gradually transition from large amount of elastic tissue and less smooth muscle to less elastic tissue and more smooth muscle; consists of elastic arteries, muscular arteries, and arterioles

·         Veins

o   Structure: thin walls with a large lumen; contains less elastic tissue and fewer smooth muscle cells than arteries; consist of venules, small veins, medium and large veins, and portal veins; contains valves

·         Capillaries

o   Structure: one epithelial layer of simple squamous cells on a basement membrane with connective tissue outside attaching it to tissues; thinnest blood vessel type; may have precapillary sphincters (smooth muscle); types: continuous, fenestrated, sinusoidal

·         Venules

o   Structure: tubes composed of endothelium resting on a delicate basement membrane, a few isolated smooth muscle cells exist outside the endothelial cells

·         Arterioles

Structure: smallest arteries, transport blood from small arteries to capillaries and are capable of vasodilation and vasoconstriction

·         Blood flow influences

o   Increase caused by an in pressure, decrease in resistance to the area

·         Blood pressure influences

o   Increase caused by increase in cardiac output, increase in blood volume, increase in peripheral resistance

o   Peripheral resistance increased by increase in viscosity, increase in vessel length, decrease in vessel diameter, increase in turbulence

·         Regulation Methods

       a) Autoregulation – vasodilation caused by metabolic need, vasoconstriction caused by muscle cell response or chemicals released by tissues or cells

       b) Neural regulation – detected by proprioceptors, baroreceptors, and chemoreceptors; reflexes carried by cardiac (sympathetic) or vagus (parasympathetic) nerves to the cardiovascular centers in the brain stem motor nuclei (cardiac center – cardioacceleratory, cardioinhibitory; vasomotor center)

       c) Hormonal regulation-(renin-angiotensin-aldosterone system, epinephrine/norepinephrine, ADH, ANP, erythropoietin)

·         Autoregulation: maintenance of blood flow by tissues; relatively constant compared to arterial pressure

o   Regulated by need for nutrients and oxygen (not by blood pressure)

o   If need remains elevated, diameter and number of capillaries can increase in that tissue (ex: in skeletal muscle of athletes)

·         Nervous Control of Blood Flow

o   Blood pressure maintenance by nervous system - minute-to-minute regulation

o   Important during exercise (blood flow to skeletal muscles increases greatly)

o   Important in shunting blood from one large area to another (ex: blood loss, blood shunted to brain and heart to maintain blood pressure and life)

o   Autonomic nervous system (sympathetic) - vasomotor fibers innervate all vessels except capillaries, precapillary sphincters, most metarterioles

§  Prominent in the kidneys, digestive tract, spleen, skin

o   Vasomotor center: located in the lower pons/upper medulla oblongata; excitatory part is tonically active (continuous, low baseline level of action potentials via sympathetic vasoconstrictor fibers causes vasomotor tone - constant partial vasoconstriction of peripheral blood vessels) and inhibitory part (vasodilation)

§  Hypothalamus → strongly excites or inhibits

·         Temperature receptors → vasodilation in skin

§  Cerebral cortex → excites or inhibits

·         Emotional excitement (action potentials begin in cerebral cortex) activate hypothalamus → vasoconstriction/increase in vasomotor tone

o   Neurotransmitter of vasoconstrictor fibers: norepinephrine (binds mostly to alpha-adrenergic receptors on vascular smooth muscle cells to cause vasoconstriction)

§  Sympathetic action potentials release epinephrine and norepinephrine into blood from adrenal medulla in addition to norepinephrine via vasoconstrictor fibers

Review the process of capillary exchange. What are forces regulating bulk flow?

What roles do diffusion and transcytosis play

·         Bulk flow – flow of materials under pressure

·         Net flow out near the beginning of the capillary higher than the net flow in near the end of the capillary (Starling's law of the capillaries); osmotic pressure moving water in because of higher solute concentration stays constant throughout vessel, but blood pressure (hydrostatic pressure) is higher at the beginning of the capillary in order to overtake the forces of osmotic pressure and physically push more fluid out than comes in

·         Summary – hydrostatic pressure causes net outflow at the beginning while osmotic pressure causes smaller net influx near the end; remainder of the fluid goes to the lymphatic system

·         Transcytosis is exocytosis on one side and endocytosis on the other

Describe the structural features that make RBCs highly specialized for O2 transport

·         4 globin (protein chains) attached to 4 heme (porphyrin ring containing nitrogen with a single nitrogen in the center that can bind and unbind oxygen); appears as a flexible biconcave disc (to increase surface area and create less space over which diffusion must occur)

Describe the different types of white blood cells, their relative numbers, and their

functions

·         Granulocytes

o   Neutrophils – phagocytosis; multilobed nucleus with light-staining granules, fairly large cell; most common: 60-70%

o   Eosinophils – decreasing allergic reactions and killing parasitic worms; bilobed nucleus with red-staining granules: 2-4%

o   Basophils – release of histamine (allergic reactions); dark-staining granules that obscure the nucleus; rarest: 0.5-1%

·         Agranulocytes

o   Lymphocytes – B cells produce antibodies (as plasma cells) and T cells kill invaders (cytotoxic) and increase effectiveness of immune system (helper); round nucleus with cytoplasmic ring outside: 20-25%

o   Monocytes – phagocytosis over longer period of time; horseshoe shaped nucleus, very large cells: 3-8%

·         Vascular phase – vascular spasm as a result of the tunica media's smooth muscle reflexively constricting when cut

·         Platelet phase – platelet adhesion (binding to collagen), platelet release reaction (chemicals likethromboxanes, serotonin, and ADP released), platelet aggregation (platelets stick to one another and continue to release chemicals, form a plug)

·         Coagulation phase – blood clot formed when fibrinogen becomes fibrin

List the muscles involved in inhalation and exhalation and their actions

·         Inhalation: diaphragm, external intercostals, pectoralis minor, and scalenes. Contraction of the diaphragm is responsible for 2/3 of the increase in thoracic volume, the external intercostals, pectoralis minor, and scalenes muscles also increase thoracic volume by increasing the ribs 

·         Exhalation: internal intercostals and transverse thoracis, depresses the ribs and sternum

·         The primary functions of the muscles is to stiffen the thoracic wall by contracting at the same time

Describe the pressure changes (alveolar and intrapleural) involved in pulmonary

ventilation

·         Changes in thoracic volume causes changes in the alveolar volume which causes changes in the intra-alveolar pressure

·         At the end if expiration and inspiration: intra-alveolar pressure and barometric air pressure is equal and no air movement

·         During inspiration: increased thoracic volume causes an increase in alveolar pressure and a decrease in intra-alveolar pressure so barometric air pressure is greater than intra-alveolar pressure so air moves into the lungs

·         During expiration: decrease thoracic volume causes a decrease in alveolar pressure and an increase in intra-alveolar pressure so barometric air pressure is lower than intra-alveolar pressure so air moves out of the lungs  

·         Intrapleural: Pressure inside pleural sac

o    Always negative under normal conditions

o    Always less than intra-alveolar pressure

·         The pressure of a gas is inversely proportional to its volume at a given temperature

·         Air flows from areas of higher to lower pressure; increase alveolar pressure decreases pleural pressure and air moves into the lungs

·         Decrease alveolar pressure increases pleural pressure and air moves out of the lungs 

·         Surface Tension

o   Surfactant decreases surface tension thus preventing alveolar collapse

·         Compliance

o   High compliance means the lungs and thoracic wall expand easily

o   Low compliance means that they resist expansion

·         Airway Resistance

o   Any condition or obstruction of airways that increases resistance

Define the various lung volumes and capacities

·         Tidal volume: volume of air inspired or expired with each breath

·         Inspiratory reserve volume: amount of air that can be inspired forcefully after inspiration of the tidal volume

·         Expiratory reserve volume: amount of air that can be forcefully expired after inspiration of the tidal volume

·         Residual volume: volume of air still remaining in the respiratory passages and lungs after the most forceful expiration

·         Inspiratory capacity: tidal volume+ inspiratory reserve volume= amount of air a person can inspire maximally after a normal expiration

·         Functional residual capacity: expiratory reserve volume+ residual volume= amount of air remaining in the lungs at the end of a normal expiration

·         Vital capacity: inspiratory reserve volume+ expiratory reserve volume+ tidal volume= maximum volume of air a person can expel from the respiratory tract after a maximum inspiration   

·         Total lung capacity: inspiratory+ expiratory reserve volume+ tidal volume+ residual volume

Explain Dalton’s law and how it governs the diffusion of gases in respiration. Describe the exchange of oxygen and carbon dioxide in external and internal respiration

• Dalton's Law: total pressure of gases is equal to the sum of partial pressure of component gases
• Partial pressure: pressure exerted by each type of gas in a mixture, proportional to percentage of the total that each gas represents
• Oxygen diffuses from the alveoli into the blood (lower partial pressure in blood in pulmonary capillaries because oxygen has been used up and must be reoxygenated)
• CO2- diffuses from blood into the alveoli (lower partial pressure of CO2 in alveoli, which makes up less than half a percent of atomspheric air)

·         Partial pressure

·         Diffusion of gases into and out of liquids

·         Diffusion of gases through the respiratory membrane

·         Relationship between alveolar ventilation and pulmonary capillary

Describe how oxygen and carbon dioxide is physically transported in the blood

·         Once oxygen diffuses through the respiratory membrane into the blood, most of it combines reversibly with hemoglobin, and a smaller amount dissolves in the plasma. Hemoglobin transports oxygen from the pulmonary capillaries through the blood vessels to the tissue capillaries, where some of the oxygen is released

·         Once carbon dioxide enters the blood, it is transported in three ways: dissolved in the plasma, in combination with hemoglobin or in the form of bicarbonate ions

Explain the relationship between oxygen-hemoglobin dissociation and the partial

pressure of oxygen, and describe how pH, the partial pressure of carbon dioxide,

temperature and BPG effect this relationship

·         Decreasing oxygen makes it hemoglobin has less affinity to bind to it 

·         Describes the percent saturation of hemoglobin the blood at different blood partial pressure of oxygen values

·         As blood pH decreases/increase  partial pressure of oxygen decreases/increase

·         As partial pressure of carbon dioxide increases partial pressure of oxygen decreases

·         As temperature increases partial pressure of oxygen decreases

·         As 2,3-bisphosphoglycerate(BPG) increase partial pressure of oxygen decreases

Explain how the nervous system controls breathing

• Medullary rhythmicity area:  Controls the basic rhythm of ventilation
• Dorsal respiratory group is active during inspiration and stimulates the contraction of the diaphragm
• Ventral respiratory group is active during inspiration and expiration and stimulates the external intercostals, internal intercostals, and abdominal muscles
• Pontine respiratory group: neurons located in the pons that function in switching between inspiration and expiration to fine-tune breathing rhythm

·         Excretion, regulation of blood volume and pressure, regulation of the concentration of solutes in the blood, regulation of extracellular fluid pH, regulation of vitamin D synthesis

·         Filtration occurs when blood pressure non-selectively forces water and other small molecules out of glomerular capillaries into the Bowman capsule forming filtrate

·         Tubular reabsorption occurs when the nephron specifically returns water and some filtered molecules to the blood, most of the filtered water and useful solutes have been returned to the body by the time the filtrate has been modified to urine, whereas the remaining waste or excess molecules and a small amount of water form urine

Describe the structure of the filtration membrane and the pressures that influence

glomerular filtration

·         Fenestrae of the glomerular capillary , basement membrane between the capillary wall and the visceral layer of the Bowman capsule, podocytes of the visceral layer of the Bowman capsule 

·         Membrane permeability, filtration membrane area, and net filtration pressure

Describe how glomerular filtration rate (GFR) is regulated

·         Autoregulation dampens systemic blood pressure changes by myogenic mechanism:   altering afferent arteriole diameter and tubuloglomerular feedback: correlates filtrate flow past the macula densa cells to GFR

·         Sympathetic stimulation decreases afferent arteriole diameter

Describe the transport mechanisms used in tubular reabsorption and secretion

·         Tubular Reabsorption: filtrate is reabsorbed by passive transport including simple diffusion, facilitated diffusion, active transport, and symport, from the nephron into the peritubular capillaries: the thin segment of the loop of Henle is specialized for passive transport, the rest of the nephron and collect ducts perform active transport, symport, and passive transport

o   Substances transported: active transport moves mainly sodium across the wall of the nephron, other ions and molecules are moves primarily by symport

o   Passive transport moves water, urea, and lipid-soluble, nonpolar compounds 

·         Tubular Secretion: substances enter the proximal or distal convoluted tubules and the collecting ducts

·         Hydrogen ions, K+, and some substances not produced in the body are secreted by antiport mechanism

List the hormones that regulate tubular reabsorption and secretion and describe how

they function

·         ADH regulates water permeability of principle cells in distal convoluted tubules and collecting ducts, if ADH is absent, water is not reabsorbed and a dilute urine is produced, if ADH is present, water is reabsorbed and a concentrated urine is produced 

·         Renin-Angiotensin-Aldosterone Hormone: increases the secretion of aldosterone and that enters the distal convoluted tubule, increases the synthesis of transport proteins of the apical and basal membrane, newly synthesized transport proteins increase the rate at which Na+ are absorbed and K+ and H+ are secreted. Chloride ions moves with the Na+ because they are attracted to the positive charge of Na+

Explain the role of the renal tubule and collecting ducts in producing both dilute and

concentrated urine

·         In collecting ducts, if ADH is absent, water is not reabsorbed and a dilute urine is produced, if ADH is present, water is reabsorbed and a concentrated urine is produced

·         The renal tubule is the end of the nephron. After the tubular fluid leaves the renal tubules, it passes on the collecting duct system, which connects the nephron to the ureter, through which urine is excreted

·         It's the volume of plasma that is cleared of a specific substance each minute

·         Plasma clearance= Quantity of urine x Concentration of substance in urine/Concentration of substance in plasma

Explain the anatomical and functional differences between juxtamedullary and cortical

nephrons

·         Cortical Nephron: are located in the periphery of the cortex, have relatively shorter loops of Henle which extend only up to the outer medulla

·          Juxtamedullary Nephron: are located near the corticomedullary junction, have longer loops of Henle which extend as far as to the papilla

List major electrolytes found in the body, include where they are primarily located and

what major processes they effect

·         Sodium:

o   Dominant extracellular cation.

o   Present in the same concentration in filtrate and extracellular fluid -- Na+ excreted in urine determined by amount of Na+ and water reabsorption from filtrate

o    Na+ transport (distal convoluted tubule and collecting duct) - hormonal control

§  Aldosterone: increases Na+ reabsorption into extracellular fluid

o   Na+ also excreted in sweat; not physiologically significant

§  Caused by thermoreceptors of hypothalamus increasing sweat production

o   Blood pressure in resting conditions influences Na+ and water excretion (low BP indicates low Na+)

§  Renin-angiotensin-aldosterone mechanism activated to decrease Na+ and water excretion if BP low

§  ANP secreted by right atrium to increase Na+ and water excretion if BP ishigh (also inhibits ADH secretion and effects on tubules)

·         Chloride:

o   Helps balance anions in different compartments

o   Passively follows Sodium so its regulated indirectly by aldosterone levels

o   ADH helps regulate Chloride in body fuilds because it controls water loss in urine

·         Potassium:

o   Helps establish resting membrane potential and repolarize nerve and muscle tissue

o   Exchange for hydrogen ions to help regulate pH in intracellular fluid

o   Control is mainly by aldosterone which stimulates principal cells to increase potassium secretion into the urine

·         Bicarbonate:

o   Major buffer in plasma

o   Concentration increases as blood flows through systemic capillaries due to carbon dioxide released from metabolically active ceils

o   Concentration decreases as blood flows through pulmonary capillaries and carbon dioxide is exhaled

o   Kidneys are main regulator of plasma levels

·         Calcium:

o   Important role in blood clotting, neurotransmitter release, muscle tone, and nerve and muscle function

o   Regulated by parathyroid hormone and calcitonin

§  PTH stimulates osteoclasts to release calcium from bone

§  PTH increases production of calcitriol

·         Phosphate:

o   Present as calcium phosphate in bones and teeth, and in phospholipids, ATP, DNA, and RNA

o   HPO₄^2- is important intracellular anion and acts as buffer of hydrogen ions in body fluids and in urine

o   Plasma levels are regulated by parathyroid hormone and calcitriol

§  Resorption of bone release phosphate

§  In the kidney, PTH increases phosphate excretion

§  Calcitriol increases GI absorption of phosphate 

·         Magnesium:

o   Found in bone matrix and ions in body fluids

o   Urinary excretion increased in hypercalcemia, hypermagnesemia increased extraceullar fluid volume, decreases in parathyroid hormone and acidosis

Discuss the mechanisms that allow the body to maintain its normal pH, and how these

mechanisms function to reduce or increase hydrogen ion concentration

·         Chemical buffer system:

o   Resists changes in pH

§  When hydrogen ions are added to a solution, the buffer removes them

§  When hydrogen ions are removed from a solution the buffer replaces them  

§  3 important buffers:

·         Protein buffers: intracellular and plasma

·         Carbonic acid-Bicarbonate buffer: intracellular, extracellular, and plasma buffer

·         Phosphate buffer: main intracellular buffer, buffer in urine

o   Respiratory system:

§  Exhalation of carbon dioxide

o   Urinary system:

§  Excretion of hydrogen ions

Explain acid-base imbalance and how the lungs and kidneys compensate to normalize

arterial blood pH

·         Acidosis--blood pH below 7.35

o   Causes depression of CNS--coma

·         Alkalosis-- blood pH above 7.45

o   Causes excitability of nervous tissue--spasms, convulsions and death

·         Respiratory compensation:

o   Respiratory regulation of Ph is achieved through the carbonic acid-Bicarbonate buffer system

·         Renal compensation:

o   The secretion of hydrogen ions into the filtrate and the reabsorption of bicarbonate ions into extracellular fluid causes extracellular pH to increase

o   Bicarbonate ions in the filtrate are reabsorbed

o   The rate of hydrogen ion secretion increases as body fluid pH decreases or as aldosterone levels increases

o   Secretion of hydrogen ions is inhibited when urine pH falls below 4.5

·         fluid balance, lipid absorption, defense

·         Fluids tend to move out of blood capillaries into tissue spaces excess fluid passes through the tissue spaces and enter lymphatic capillaries to become lymph

·         Lymph flows through lymphatic vessels to lymph nodes where it is filtered, enters the right lymphatic duct or thoracic duct then into the blood

Describe the structure and function of the lymphatic organs and structures, including the

spleen, thymus, lymph nodes, and various lymphatic nodule

·         Spleen: has an outer capsule of dense irregular connective tissue and small amount of smooth muscles, it stimulates lymphocytes in the white pulp, foreign substances and defective RBC are removed from the blood by phagocytes in the red pulp, spleen is a limited reservoir for blood  

·         Thymus: has a cortex and medulla; lymphocytes in the cortex are separated from the blood by reticular cells, produced in the cortex migrate through the medulla, enter the blood, and travels to other lymphatic tissues, where they can proliferate

·         Lymph nodes: a dense connective tissue capsule surrounds each lymph node, made up cortex and medulla, filters lymph 

·          Lymphatic nodule: are denser arrangements of lymphatic tissue organized into compact,

o   Peyer patches are aggregations of lymphatic nodule in the distal half of the small intestine and the appendix

o   MALT: mucosa-associated lymphoid tissue