PHYAN Exam 3

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How does the endocrine system influence cells?: by releasing hormones into the blood
What does the brain do other than regulate organ systems?(4): -Integration of senses (sight, smell, hearing)
-Emotions, thoughts, memories, dreams
-able to devise complex technology
-is ignorant of itself (we have no idea how our brain works!)
What are the general fxns of the nervous system? (4): -Sensory input
-Integration
-Motor output
-Has ability to store experiences (memory) and learn
2 main divisions of Nervous System. . .: CNS - brain & spinal cord
PNS - everything else
2 divisions of PNS: -Sensory (afferent)
-Motor (efferent)
2 divisions of efferent: Somatic Nervous System
Autonomic Nervous System
2 divisions of Autonomic NS: Sympathetic NS
Parasympathetic NS
Another word for Sympathetic NS?: fight or flight
Another word for Parasympathetic NS?: rest and digest
What does the somatic division do?: conveys impulses to skeletal muscle

VOLUNTARY CONTROL
What does the autonomic division do?: carries impulses to smooth and cardiac muscles & glands

INVOLUNTARY CONTROL
What is a neuroglial cell?: nonexcitable cell that supports, insulates and protects

reproduces throughout life

don't transmit electrical impulses
What is a neuron?: excitable nerve cells that recieve and transmit electrical impulses

Amitotic
What does a neuron depend on?: oxgenated blood supply

b/c:
-can't store glycogen
-can't use anaerobic metabolism
Neurons have 2 common features, what are they?: -Cell body (soma)
-Processes (dendrites, axon)
What are the 2 common features of the neuron?: Cell body (soma)

Processes (dendrites & axon)
What is a soma?: an enlarged portion of the neuron containing the nucleus
What are processes of the neuron?: fibers extending from the cell body
-"recieving end" of neuron -recieve signals from other neurons & transmits them to cell body -neurons may have hundreds: Dendrites
-generates and transmits nerve impulses away from cell body -neurons usually only have 1 -may be microscopic to 4 ft long: Axon
Distal end of axon branches profusely into: axonal terminals
when impulses reach axonal terminals they stimulate the release of chemicals called: neurotransmitters (secreted into extracellular space)
axon terminal is seperated from the next neuron or effector by: a tiny gap & synaptic cleft (neurons don't touch eachother)
the junction between neurons is called: a synapse
most axons are: myelinated
white, fatty sheath covering axons: myelin sheath
what does the myelin sheath do?: -protects and insulates neurons from other neurons
-speeds transmission rate of nerve impulse
gaps in the myelin sheath r called: Nodes of Ranvier
myeling sheath around axons r destroyed; they become sclerotic (hardened & nonfunctional; ability to use muscles lost; autoimmune disease; PRO in myelin sheath is attacked; not curable: Multiple Sclerosis
What can help multiple scerosis?: oral doses of bovine myelin
a cluster of cell bodies in the CNS: nucleus
a cluster of cell bodies in the PNS: ganglion
cluster of fibers in the CNS: tract
cluster of fibers in the PNS: nerve
cell body is damaged when cell body dies because: neurons don't go through cell division
a collection of myelinated fibers (a tract): white matter
a collection of cell bodies & myelinated fibers: gray matter
a nerve impulse causes a: muscle action potential
what are the steps to a muscle action potential?: 1) release of acetylcholine
-arrival of the acion potential causes exocytosis of synaptic cleft
-liberating Ach, which diffuses across cleft
2)Activation of Ach receptors
-Ach binds to its receptor
-Na+ channels in sarcolemma open and Na rushes into the muscle
3)Production of muscle action potential
-influx of Na+ causes depolarization of the muscle cell
-triggers a muscle action potential & contraction
4)Termination of Ach activity
-Ach is rapidly broken down by an enzyme called Acetylcholinesterase (AChE) which is present in the synaptic cleft
Several drugs & toxins block events in the . . .: Neuromuscular Junction (NMJ)
One of the most lethal chemicals known; produced by bacteria that proliferates in improperly canned foods; blocks exocytosis of synaptic vesicles at the NMJ; Ach isn't released, muscle contraction doesn't occur; tiny amts cause death by paralyzing the di: Butulinium Toxin
a plant derivative; is used by South American Indians on darts; binds to and blocks the Ach receptor but sarcolemma premeability to Na isn't changed; no influx of Na+, no muscle contraction; paralysis; often used during surgery to relax muscles: Curare
Which disease is derived from a plant?: Curare
Inhibits acetylcholinesterase; it slows removal of Ach from the synaptic cleft so more Ach is available to bind with receptors: Anticholinesterase agents
What do anticholinesterase agents do?: 1) treats Myasthenia gravis
2) reversal of curare poisoning
what is a reflex arc?: the neural pathway over which a reflex occurs
Simple reflex arc: 1) receptor
2) sensory (afferent) neuron
3) integration center (CNS)
4) motor (efferent) neuron
5) effector organ
when the reflux activates skeletal muscle it is a ________ reflex: somatic
when the reflux activates smooth or cardiac muscles or glands r activated it is a _______ reflex: autonomic (visceral) reflex
What r nerves?: -a bundle of nerve fibers (axons) w/ their CT wrappings
-found outside CNS
what is are mixed nerves?: both motory and sensory fibers
(they go both directions)
what do the nervous and endocrine systems do together?: they regulate functions of other body systems by chemical means
Hormones travel everywhere blood goes. . .what does that mean?: they're nonspecific
secrete their products through a duct onto a body surface; "secretions" NOT hormones; ex: mucous, seat, oil, saliva etc): exocrine glands
r ductless, secrete hormones into surrounding tissure fluid; have a rich vascualr supply to recieve hormones: endocrine glands
What's a hormone?: a chemical messenger secretes into the extracellular fluid and then picked up by the blood
What do hormones do?: regulate the metabolic functions of he cells throughout the body
What r the 2 major types of hormone?: 1) amino acid based hormones
2) steroid hormones
may be simple amino acid derivatives, peptides or PRO: amino acid based hormone
made from cholesterol; sex hormones (gonadal), the hormones produced by the adrenal cortex: steroid hormones
Hormones circulate through the blood but only affect certain tissue cells or organs called: target cells or target organs
the target cell/organ must have a specific PRO recepto for that hormone, either . . .: -on its plasma membrane
-in its interior
When hormone binds to its target it. . . .: alters the cells activity
What are the ways hormones change cell activity? (4): 1) changes in plasme membrane permeabilty or electrical state
2) synthesis of PRO or NZs in cell
3) activation/inactivation of NZs
4) stimulation of mitosis
Steroid Hormone Action: -diffuse through plasma membrane
-enter nucleus
-bind to specific receptor PRO
-hormone & receptor then bind to specific sites on DNA
-activates certain genes to transcribe mRna
-mRna moves to cytoplasm resulting in the synthesis of new PRO
Amino Acid Based Hormone Action: -bind to their specific recepto PRO in the plasma membrane
-this causes an NZ to be activated
-which catalyzes a Rxn that produces a 2nd messenger inside the cell
-causes additional intracellular changes
Blood levels of hormones are regulated by: Negative feedback mechanisms
3 types of stimuli that activate endocrine organs. . .: 1) hormonal stimuli
2) humoral stimuli
3) neural stimuli
Hormonal Stimuli: -hormones from other gland stimulate an endocrine gland
-many hypothalamic hormones stimulate the pituitary
Humoral Stimuli: -changing blood levels of nutrients and some ions
-low blood Ca levels causes the parathyroid gland to secrete
Neural Stimuli: some endocrine glands r stimulated by nerves to secrete
What are the 2 hormones the hypthalamus synthesizes?: 1) Oxytocin
2) Antidiuretic Hormone
Oxytocin and ADH hormone are stored and released from the: posterior lobe of the pituitary gland
Which hormone is only released during childbirth & in nursing women?: Oxytocin
- Uterus (stimulates labor contractions)
- Breasts (initiates milk ejection)
The target organ for ADH is: the kidneys
pea-shaped gland hanging by a stalk from the hypothalamus; Suspended in the sella tursica of the sphenoid bone: Pituitary Gland
what does the posterior pituitary lobe do?: stores and releases hypothalamic homrones
-not a true gland b/c it doesn't synthesize hormones
What does the anterior pituitary lobe do?: synthesizes and secretes 6 hormones
-all r PRO
-all r regulated by hormonal stimuli & usually by neg. feedback
What r the 4 tropic hormones of the pituitary gland?: 1) thyroid stimulating hormone (TSH) or Thyrotropin
2) Adrenocorticotropic Hormone (ACTH)
3) Follicle Stimulating Hormone (FSH)
4) Luteinizing Hormone (LH)
-Thyrotropic -Stimulates growth & activity of the thyroid: TSH - Thyroid Stimulating Hormone or thyrotropin
-Corticotropic -Stimulates the adrenal cortex to release corticosteroids: ACTH - Adrenocorticotropic Hormone
-Gonadotropic -Stimulates te gonads (ovaries & testes): FSH - Follicle Stimulating Hormone
What does FSH stimulate in the ovaries?: -Stimulates follicle maturation & ovulation
-follicle produces estrogen
What does FSH stimulate in the testes?: Sperm production
Luteinizing Hormones are: Gonadotropic
What does LH do for the ovaries?: -Promotes estrogen & progesterone production & secretion
What does LH do for teh testes?: -Stimulates testosterone secretion
Hyposecretion of Growth Hormone or Somatotropin during childhood causes. . .: dwarfism
Hypersecretion of GH or Somatotropin causes . . .: Gigantism
Hypersecretion of GH or Somatotropin in adults causes. . .: Acromegaly
Hypersecretion of GH or Somatotropin usually results from: a tumor in the organ
What are the 2 non-tropin hormones in the pituitary gland?: 1) growth Hormone (GH) or Somatotropin
2) Prolactin
What are the major targets of GH?: -Bones - long bone growth (epiphyseal plate)
-Skeletal muscles - increased muscle mass
What does prolactin stimulate?: milk production
When is prolactin stimulated?: secretes immediatley after child birth & while nursing
What does the thyroid gland secrete?: thyroid hormone
What kind of hormone are GH and Prolactin?: PRO hormones
what happens when you have hypthyroidism?: -physical/mental sluggishness
-low body temp

treatment - oral doses of thyroxin
What happens if you have hyperthyroidism?: -high metabolic rate
-weight loss
-nervous, agitated, hot
-rapid heart rate
What is the treatment for hyperthyroidism?: -removal of part of the thyroid
-administer radioactive iodine to destroy cells
Thyroid gland secretes. .: -thyroid hormone
-calcitonin
Calcitonin is secreted in response to: -high blood Ca levels
-causes Ca to be deposited to bones
-may be diminished in the aged
Where is the parathyroid gland located?: behind the thyroid
Which hormone does the parathyroid secrete?: Parathyroid hormone
What does parathyroid hormone or parathormone do?: increases blood Ca levels
What does parathyroid hormone stimulate?: -osteoclasts to resorb bone & releas Ca to blood
-kidneys to inhibit urinary Ca excretion
-Intestinal cells to increase absorption of Ca
What is the inner region of the Adrenal glands called?: adrenal medulla
What is the outer region of the adrenal glands called?: adrenal cortex
The adrenal cortex stimulates how many steroid hormones?: 25+
-which are called corticosteroids
-derived from cholesterol
3 categories of coticosteroids: -Mineralcoticoids
-Glucocorticoids
-Gonadocorticoids
Mineralcorticoids are secreted when. . . And stimulates. . .: Na blood level is low

stimulates kidneys
-promote Na retention
-increase water retention
-promotes K secretion
Principal hormone for mineralcoticoids is: Aldosterone
Glucocorticoids are secreted. . .: In response to ACTH & to stress
-causes rise in blood levels of glucose and fatty acids
-encourages use of fats for NRG needs
-Saves glucose for brain
-anti-inflammatory effects
What r the principal hormones for glucocorticoids?: -Cortisol
-Corisone
Gonadocorticoids are: weak sex hormones, mainly androgens
-amts. insignificant
FXN UNCLEAR
Pancrea is located: below and behind the stomach
Endocrine cell clusters are called: Pancreatic islets
Pancreas secretes 5 pancreatic hormones but the 2 most important are:: -Insulin
-Glucagon
Insulin is secreted by: Beta Cells
-in response to a "fed" state
-stimulates transport of glucose into cells
-lowers blood glucose
Glucagon is secreted by: Alpha cells
-in response to "fasting" state
-stimulates fat breakdown & release into the blood
-increase blood glucose levels
Steroid sex hormones are stimulated by: gonadotropic hormone from the anterior pituitary (FSH/LH)
Pineal Gland is located: in the center of the brain
Main secretion of pineal gland is: Melatonin
Melatonin: FXn unclear
blood levels peak at night
-large in children, shrinks as we age
Thymus gland is located under: the sternum
-large in children & reduces with age
The main hormone secreted by the thymus is: Thymosin
Thymosin is: essential for normal immune response
-regulates activation of T lymphocytes (disease fighting blood cells)
According to structure what are the 3 types of neurons?: -multipolar
-bipolar
-unipolar
According to FXN, what are the 3 types of neurons?: -afferent
-efferent
-interneurons
Neurons are:: -irritable (rspond to a stimulus)
-conductive (conduct electrical impulse down the axon
-secretory (secrete chemicals)
saltatory conduction is when: action potentials jump over myelin (node to node)
When axons are unmyelinated it makes conduction: much slower
Skeletal muscles must be: -innervated
-stimulated by a motor neuron
the NMJ synapse is between: a somatic motor neuron & muscle fiber
Axon terminal contains: tiny synaptic vesicles
-membrane-bound sacs
-contain the neurotransmitter
The neurotransmitter at the NMJ is: Acetylcholine
What does the adrenal medulla secrete?: epinephrine and noneepinephrine
What do epinephrine and nonepinephrine do?: -increse blood glucose levels
-increse heart rate
-blood vessels constrict, diveting blood from nonessential organs TObrain, heart & skeletal muscle

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