• controls homeostasis
• maintains water balance
• controls uterine contractions
• controls milk production
• regulates ions (calcium, sodium, potassium)
• regulates metabolism and growth
• regulates heart rate and blood pressure
• monitors blood glucose levels
• aids the immune system
• reproductive functions

molecules that are released from one location, move to another location, and produce a response.

Two types

• intracellular: produced in one part of a cell and moves to another part of the same cell. occures as a result of intercellular signals. after a intercellular signal enters a cell intracellular signals take over.
• intercellular: released from one cell and binds to receptors on another cell.                (enters another cell)

What are the types of intercellular signals?

(enters other cells)

• autocrine
• paracrine
• neurotransmitter and neuromodulators
• pheromones
• hormones and neurohormones

• Type of intercellular signal
• released by cells and have a local effect on the same cell type
• eicosanoids (prostaglandins, thromboxanes, prostacycline, leukotrienes)

• type of intercellular signal
• released by cells that affect other cell types in close proximity
• examples somatostatine (inhibits insulin secretion)
• also histamine, and eicosanoids

• intercellular signal
• nervous system function
• produced by neurons;secreted into a synaptic cleft by presynaptic nerve terminals; travels shot distances; influences postsynaptic cells
• examples acetylcholine, epinephrine

• type of intercellular signal
• secreted into enviroment and modify behavior and physiology of other indiviual in same species
• example: women and menstrual cycles

• type off intercellular signals
• secreted into blood and bind to receptor sites
• examples epinephrine and insulin

• type of intercellular signal
• secreted into the blood by specialized cells; travels some distance to target tissues; results in coordinated regulation of cell function
• examples: thyroid hormones, growth hormones, insulin, epinephrine, etrogen, progesterone, testosterone, prostaglandins

Episodic secretion is generally associated with hormones under nervous control. When nerves of the hypothalamus fire, neuropeptides are released in a sudden burst or pulse.

I have an episode over my exam every time, where I get nervouse!

• receptor site: the locatin on a cell where hormones bind (lock)
• target tissues: group of cells that respond to specific hormones
• specificity: specific hormones bind to specific receptor sites

• hormones are secreted by endocrine glands directly into bloodstream
• they travel to all parts of the body
• homones (the key) bind to receptor site (the lock) on target tissues
• a response occurs

• the duration of secretion
• the half-life
• the receptor density (how many receptors are available to be bound)
• receptor-hormone affinity (and beyond)

• alter cell activity of target tissues by increasing or decreasing cell's normal processes
• change permeability of cell membrane by opening or closing ion channels
• synthesis of proteins

1. water soluble hormones
2. lipid soluble hormones

• include proteins, peptides, amino acids
• the most common type of hormone
• travel freely in the blood stream but require receptors to cross over fatty (lipid) membranes {membrane bound receptors}
  
•  since they cannot move through intestinal membrane and will be broken into amino acids they must be injected
• examples: growth, antidiuretic, prolactine, etc.
• G protein complex

• include steriods and eicosanoids
• examples: LH, FSH, androgens, estrogens
• require assistance to travel through the blood steam but diffuse easily across the fatty (lipid) membranes of cells
  
• since move intact through intestinal membranes they can be taken orally
• {Bind to nuclear receptor}
  

1. carried through the blood attached to protein carriers
2. diffuse through the plasma membrane
3. bind to cytoplasmic receptors and travel to the nucleus (alternatively: bind to nuclear receptors)
4. hormone-receptor complex binds to a hormone response element on the DNA, acting as a transcription factor
5. the last step stimulates the synthesis of mRNA which codes for specific proteins
6. at this point the mRNA leaves the nucleus, enters the cytoplasm and binds to ribosomes, where it directs the synthesis of specific proteins
7. the protins produce the cell's response to the lipid soluble hormones (example: secretion of new proteins)

1. water soluble hormones float freely through the blood stream looking for receptors to bind to
2. before the water soluble hormone binds, the G protein consists of 3 subunits with GDP attached to the last subunit and freely floats in the plasma membrane
3. when the hormone binds to the membrane bound receptor the receptor changes shape and the G protein binds to it. This causes GTP to replace the CDP on the last subinit of the G protein
4. The G protein separates from the receptor. The GTP-linked subunit activates cellular response (vary among target cells)
5. GTP bound subunit binds/activates an adenylate cyclase enzyme that converts ATP to cAMP
6. cAMP activates protein kinase enzymes, that phosphorlate specific enzymes activating them.
7. the chemical reactions catalyzed by the activated enzymes produce the cell's response.
   
8. phosphodiesterase enzymes inactivate cAMP by converting cAMP to AMP
   
9. when the hormone separates from the receptor additional G proteins are no longer activated and the inactivated last subunit loses a phosphate (the GTP turns to GDP) setting up for the cycle to restart.
   

• activated G proteins (3)
• Activated Adenylated cyclase (10)
• cAMP (21)
• Activated protein kinase enzymes (36)

1. Humoral stimuli: blood levels of chemicals (blood glucose levels [insulin])
2. Hormonal stimuli: other hormones (TSH signals thyroid gland to release thyroid hormone)
3. Neuronal stimuli: Nervous system (epinephrine and fight or fligh response)

1. neurons in hypothalamus release stimulatory hormones (releasing hormones) that travel in the blood to the anterior pituitary gland
2. then these hormones stimulate the release of hormones from the antirior pituitary, which travel in the blood to their target endocrine cell
3. the target endocrine cell secretes its hormone into the blood, where it travels to its target and produces a response

• hormone inhibits (stops) the activity of another hormone
• hormone from the target endocrine cell has a negative effect on the anterior pituitary and hypothalamus and decreases secretion of the tropic hormone, as it also releases hormone that travels to the target.

• hormone that promotes the activity of another hormone
• hormone from the target endocrine cell has a positive effect on the anterior pituitary and increases secretion of the tropic hormone, as it also releases hormone that travels to the target.

• pituitary (brain)
• pineal gland (brain)
• hypothalamus (brain)
• thyroid (neck)
• parathyroids (posterior of thyroid)
• thymus (above heart)
• adrenals (atop kidneys)
• pancreas (by kidneys)
• ovaries
• testes

• thyrotropin-releasing hormone (TRH)
• Gonadotropin-Releasing hormone (GnH)
• Growth hormone-Releasing hormone (GHRH)
• Corticotripin-Releasing Hormone (CRH)
• somatostatin
• Dopamine

(3 hormone types: inhibiting, releasing, and tropic)

• Definition: the capillary beds and veins that transport the releasing and inhibiting hormones
• (Neurons of the hypothalamus produce and secrete neurohormones (inhibiting or releasing) that act on cells of the anterior pituitary gland (leave the capillaries binding to membrane bound receptors), that cause the A.P. to secrete hormones of it's own, that are carried in the blood to target tissues possible other endocrine glands)
• allows minute amounts of hormones to act on the anterior pituitary without diluting GnRH
  
  

• hormone of the hypothalamus
• Stimulates the release of thyroid stimulating hormone (TSH) and Prolactin from the A.P.
• function: TSH-metoabolism (thyroid: regulates secretion of thyroid)          Prolactin-Lactation (mammary glands)

• hormone of the hypothalamus
• stimulates or inhibits (dependent on secretion manner) Follicle Stimulating Hormone (FSH) and Lutenizing Hormone (LH) from the A.P.
• function: ovarian secretion of estrogen and progeserone....testicular secretion of testosterone

• hormone of the hypothalamus
• stimulates the release of growth hormone (GH) from the A.P.
• function: muscles and bone growth

• hormone of the hypothalamus
• stimulates the release of adrenocorticotropic hormone (ACTH) from the A.P.
• function: adrenal cortex: glucocorticoies (cortisol), mineralocorticoids (aldosterone), androgens (testosterone)
• function: fetal: DHEA-s labor

• hormone of the hypothalamus
• inhibits the release of GH and TSH from the A.P.
• function: decrease growth

• hormone of the hypothalamus
• inhibits the release of prolactin from the A.P.
• function: decreases lactation

• small gland in brain
• controlled by hypothalamus
• divided into two regins: anterior and posterior
• secreates atleast 6 hormones

• stimulated by thyrotropin releasing hormone (TRH) of the hypothalamus) released by the A.P. and effects the thyroid gland
• too much=enlarged thyroid
•  too little=shrink thyroid 
  
• (TSH) cause the increased release of T3 and T4 from thyroid into circulation
• T3 and T4 inhibit the secteation of TSH from hypothalymus (Negative feedback)
• target tissue: increase metabolism, increase body temperature, increase normal growth and development
  

• stimulated by Gonadatropin releasing hormone (GnRH) from the hypothalamus, release by the A.P. and effects the ovaries and testes
• Luteinizing (LH) in females targets the ovaries, promoting ovulation and progesterone production, in males it targets the testes, promoting sperm production and testosterone
• Follicle-stimulating (FSH) in females targets follicles in ovaries promoting follicle maturation and estrogen secretion in males it targets seminiferous tubules of testes, promoting sperm production
• Positive feedback

• stimulated by dopamine released by the hypothalamus, it is released by the the A.P. and effects the mammary glands and ovaries or testis in males
• functions: milk production, prolongs progesterone secretion post-ovulation and pregnancy, increases LH sensitivity in males (aids for LH recepters to be more aware of LH increasing sperm production)

• stimulated by the corticotropin releasing hormone (CRH) from the hypothalamus, released by the A.P. and effects cells of the adrenal cortex (through membrane bound recepotrs) and melanocytes of the skin
•  function:stimulate glucocorticoids (cortisol) production (stress hormone) fetal ACTH induces labor, and increases skin pigmentation

• stimulated by growth hormone releasing hormone (GHRH) from the hypothalums released by A.P. and effects most tissues
• function: stimulates growth of bones, muscles, and organs
• too much causes giantism
• too little causes pituitary dwarfism

1. the hypothalamic nerve cells are stimulated by the nervous system to produce an action potential
2. action potentials are carried by axons of nerve cells to the P.P. (axons of nerve cells store hormones in the P.P.)
3. P.P. gland action potential causes the release of hormones from the axons into the circulatory system
4. hormones pass through the circulatory system and influence the activity of target tissues

• stimulated by the action potential of the hypothalamus, released by the P.P. and targets the kidneys
• function: conserve water
• Diabetes insipidus: low ADH, kidneys produce large amounts of dilute urine and can lead to dehydration and thirst
• alcohol intoxication causes ADH levels to drop resulting in increased urination and dehydration, the hangover increases ADH levels resulting in water retention and puffiness (can also happen with caffeine)

• stimulated by the action potential of the hypothalamus, released by the P.P. and targets the uterus, epidiymis, mammary aveoli (smooth muscle cells)
• function: increases uterine contraction during labor, increases sperm transport prior to ejaculatio, increases milk-let down
  

• reproductive hormones
• estrogen is a FSH in females
• Progesterone is a LH in females
• target: most
• functions: Uterus: menstrual cycling, Ovary: ovulation, Mammary: lactation and growth, Bone: strength and repair, brain: cognition and memory, Heart: prevents heart disease

comprised of two parts the Theca internal cell and the Granulosal cell.

• Theca internal cell:outer most
• Granulosal cell:more inner

communication between the two is critical for regulation of ovulation

signals sent to the...

• brain increase: lordosis, phonation, physical activity (pressure to back causes animals to freeze)
• reproductive tract increases: blood flow, edema of tissues, secretion, luekocytes, smoth muscle motility, growth of uterine glands

• reproductive hormone
• stimulated by the adrenocorticotropic hormone (ACTH) of the A.P. secreted by the inner layer of the adrenal cortex
• target: most
• function: Males: secondary sexual characteristics/ Females: sex drive

• stimulated by the release of LH from the A.P. released from the testes, and aids in sperm and reproductive organ development and function
• target: most

• cells of the seminiferous tubular of the testies, function is to nourish the sperm through stages of spermatogenesis.
• produces inhibin = negative feedback on A.P. supressing FSH

• a gland located superior and posterior to the thalamus of the brain
• produces melatonin which has negative feedback on hypothalamus decreasing the release of GnRH which effects the A.P. decreasing LH and FSH production thus inhibits reproductive functions
• target: hypothalamus
• function: role in the onset of puberty and controls circadian rhythms. Light affects its function.

• effects on the pineal gland from light sensitivity cause both...
• anestrus: long photoperiods breeders (spring/summer) 
• cyclicity: short photoperiods breeders (fall/winter)

relative blood concentration of E2

• Polyestrus=high levels all year around (cow, pig, rodents)
• seasonal polyestrus (long day) = high levels in spring/summer (mare)
• seasonal polyestrus (short day) = high levels in autumn/winter (ewe, doe, elk)
• monoestrus= high levels only once a year (dog, wolf, fox, bear)

• endocrine organ
• stimulate ovarian function
• maintain pregnancy
• influence fetal growth
• stimulate mammary function
• assist in parturition (child birth)
• produces progesterone
• produces lactogen in blood, lactogen properties promotes mammary functions, the somatotropic properties promotes fetal growth

• human chorionic gonadotropin peaks at about 2.5 months of gestation (corpus lutum assumes primary responsibility of progesterone secretion)
• 2.5 to 3 months of gestation placenta begins to assume responsibility of progesterone secretion and continues through birth. hCG increases between 5 and 9 months because placenta grows

• one of the largest endocrine glands/ palpatable
• requires iodine to function
• TRH from hypothalamus causes A.P. to release TSH that works on the thyroid
• releases T4 and T3 and calcitonin
  

thyroid follicle

(functional unit of the thyroid gland)

• follicle: single layer of epithelial cells surrounding a central lumen that contains colloid and stored hormones
• Active gland: columnar epithalium, reduced colloid (lumen space)
• Inactive gland: cuboidal epithalium, abundant colloid (lumen space)

• hormones secreted by the thyroid are thyroxine (T4) and triiodohyronine (T3)/ target most
• function: regulate metabolic rates and is needed for growth
• Negative feedback on hypothalamus (TRH) and A.P. (TSH)

• released by the thyroid
• target is the bones
• function: secreted when blood Ca2+ levels are high ... decreases rate of bone breakdown

Low thyroid hormone secretion

• decreaded metabolism
• weight gain, reduced appetite, fatigue
• low temp/pulse
• dry, cold skin
• Myxedema in adults
• cretinism in infants (dwarf apperence)

increased thyroid secretion

• increased metabolism
• weight loss, increased appetite, nervousness
• hight temp/pulse
• warm, flushed skin
• graves' disease (leads to goiter or enlarged thyroid)

• tiredness, forgetfulness/slower thinking
• moodiness/irritabiltiy
• depression, inability to concentrate
• thinning hair
• dry patchy skin
• weight gain, cold intolerance
• elevated cholesterol
• puffy eyes, swelling (goiter)
• hoarsness, voice deepens
• persistent dry/soar throat
• difficulty swallowing
• slow heartbeat
• menstrual irregularites, heavy period
• infertility
• constipation
• muscle weakness or cramps

(brookfield zoo orangutan)

• Targets the bone and kidneys
• functions to regulate blood Ca2+ levels (more than calcitonin)
• PTH binds to retnal tubules cells to increase vit D formation, vit d leads to increasing Ca absorption from intestinal epithelial cells.
• PTH binds to receptors on osteoclasts to increase osteoclast turnover, leads to resorption of bone to release Ca into blood.
• PTH binds t receptors on cells of renal tubules to decrease Ca excretion into urine

• regulates Ca levels in blood
• low Vit D means low Ca which activates PTH secretion
• more PTH leads to bone breakdown which increases Ca but leaves bones weak

• increase bone resorption
• increase Ca blood levels
• soft/deformed bones
• nerve and muscle problems (fatigue and weakness)
• inflammation
• kidney stones (excess Ca in urine)

• Decrease bone reasorption
• decrease vit D formation
• decrease Ca blood levels
• low Ca leads to nerve excitability and cramps
• if too severe major muscle may stop (heart and lungs)

• near the liver and small intestine
• produces insulin
• targets: liver, skeletal muscles, adipose tissue
• functions: regulates blood glucose leves (sugar)
• meal=high glucose levels so insulin is secreted
• extra glucose stored as glycogen
• body uses glucose from food or that our body has stored, if it is not available our body will use fats and proteins.

• juvinial onset, wasting diabetes
• too little insulin produced from pancreas, tissues cant take up glucose, beta cell defect
• Exaggerated appetite, excessive urination, dehydration, increased thirst, break down of fats/proteins. wastind of organs (muscles and brain) and lack of energy
• insulin injections

• adult onset
• lack of or defective insulin receptors on target tissue
• obesity, lethrgy, weakness
• limit intake of glucose in diet

• alpha=secretes glucagon
• beta=secretes insulin

• secreted by pancreas alpha cells
• target tissue is the liver
• function: regulates blood glucose levels
• secreted between meals when glucose levels drop
• allows glycogen to be broken down into glucose

• epinephrine and cortisol, cause synthesis of glucose through fat and protein breakdown
• growth hormone slows protein breakdown and favors fat breakdown to synthesize glucose

• after antigen is processed and presented to helper T cells, helper T cells produces interleukin-2 and interleukin 2-receptors
• interleukin-2 binds to receptors and stimulates more helper T cells production
• Helper T cells are needed to produce B cells
• B cells produce antibodies

• effective against antigens in body fluids (blood and lymph) 
• effective against bacteria, viruses, toxins
• uses B cells to produce antibodies

• Y shape 
• rotating heavy chain and light chain
• variable region V of Y
• bind to epitopes of antigen using antigen-binding site
• constant region stem of Y
• each class of immunoglobulin has same structure

• inactivate antigen
• bind antigens together
• active complement cascades
• initiate release of inflammatory chemicals
• facilitate phagocytosis

1st exposure of B cell to antigen

B cell undergoes division and forms plasma cell and memory cell

Plasma cells:

produce antibodies

3-14 days to be effective against antigen

person develop disease symptoms

• Memory cells
• occurs when immune system is exposed to antigen that has been seen before
• B memory cells quickly divided to form plasma cells which produce antibodies
• produces new memory cells
• second exposure (longer)

• effective against antigens in cells and tissues
• effective against bacteria viruses fungi and protozoa
• uses different types of T cells

activate macrophages

help form B cells

promote production of cytotoxic T cells

active:

natural exposure to antigen causes production of anitbodies

can be lifelong immunity

(mononucleosis)

Passive:

transfer of antibodies from mother to child

(breast mild or placenta)

active:

injection of antigens using vaccines which cause the production of anitbodies

Vaccine or immunization:

process of introducing killed,live,or inactivated pathogen

Passive:

injection of antibodies from another person or animal

on kidneys

2 regions medulla and cortex

adrenal medulla (inner)

epinephrine/Norepinephrine

target: heart, blood vessels, liver, fat cells

functions: released as part of fight or flight response

Adrenal cortex (outer)

aldosterone (type minealocorticoids)

target: kidneys

functions: causes Na+ and H2O to be retained and K+ to be secreted, indirectly involved with blood pressure and blood volume

glucocorticoid

targets most

functions to increase breakdown of fat and protein for energy use, reduces inflammatory and immune responses

thymus gland

Target tissues: immune system tissues

Functions: promotes immune system development and function

Doesnt change

insulin

increases

PTH

Decreases

GH

Melatonin

Thyroid hormones

Renin

Estrogen and Testosterone