ESS 3317 Exam 2

sensory fibers are also called

afferent fibers (incoming)

motor fibers are also called

efferent (outgoing)

what is the resting membrane potential

-70mV

What causes the resting membrane potential?

high Na outside cell, medium K inside cell

more negative inside

sodium potassium pump

3 Na out, and 2 K in

depolarization

when inside of the cell becomes less negative, -70-0 mV, Na enters the cell, activates the contraction

hyperpolarization

outside of the cell becomes more negative, less than -70 mV, K leaves, inhibit contraction

action potential

rapid, depolarization of neuron’s membrane, value of +30mV

inhibitory signal

K efflux, hyper polarization

excitatory signal

Na influx, depolarization

axon hillock

determines if signal is sent

dendrites

receive the signal

need 2 action potentials

from axon terminals and another after Ach enters the plasmalemma

Na gates are

closed

K gates

open

during contraction do you need to activate the sodium potassium pump?

no, because the Na gates open

depolarizing GP

-70 to -55, causing Na influx

depolarizing AP

-55 to 30, Na influx

all or none prinicple

threshold must be reached to achieve AP (-55 mV)

repolarizing AP

30 to -70, K efflux

absolute refractory period

during depolarization, neuron can’t respond to another stimulus, Na channels are open but can’t open more

relative refractory period

repolarization, neuron can only respons to strong stimulus, K channels are open, Na channels are closed but could open

fatty mylein sheath

speeds up propagation

sodium potassium pump is located by

Nodes of Ranvier (non continuous)

action potentials can only move one way

terminals contain NT that carry the AP signal across the synaptic cleft (electrical-chemical-electrical), bind to receptor on the postsynaptic surface and stimulate GP

the postsynaptic cell is the

muscle fiber

AP moves down plasmalemma, down T tubules

releases calcium, potentially cross bridge cycling

ACh

stimulates skeletal muscle contraction, mediates parasympathetic nervous system

Norepinephrine

mediates sympathetic nervous system

excitatory postsynaptic potential (ESPS)

depolarizing, excitatory, promotes AP

inhibitory postsynaptic potential (IPSP)

hyper polarizing, inhibitory, prevents AP

corpus callosum

connects the right and left hemispheres of the cerebrum, allows inter hemisphere communication

the left brain is

analytic though, language, science and math, logical

the right brain is

art and music, creative

cerebral cortex

outermost layer of cerebrum, gray matter, conscious brain

gray matter is

nonmyelinated

frontal lobe

general intellect, motor control, muscle memory

temporal lobe

auditory input, interpretation

parietal lobe

general sensory input

occipital lobe

visual input

insular lobe

emotion, self perception

primary motor cortex located in frontal lobe is

conscious control of skeletal muscle movement

cerebral white matter is

basal ganglia

basal ganglia

clusters of cell bodies in cerebral cortex, help with repetitive movements, posture, walking, running

Diencephalon is separated into

thalamus and hypothalamus

thalamus

major sensory relay center, regulates what sensory input reaches conscious brain

hypothalamus

maintains homeostasis, regulates internal environment

appetite, thirst/fluid balance, sleep, neuroendocrine control, BP, HR, breathing, temp

Cerebellum

controls rapid, complex movements, intended movements and correction

batter adjusting to pitch

spinal cord

tracts of nerve fibers permit two way conduction of nerve impulses

afferent fibers

ascending sensory

efferent fibers

descending motor

sensory divison (afferent)

transmits info from periphery to brain

mechanoreceptors

Heirng-Breur reflex- lungs stretched, inspiration is inhibited

Baroreceptor- BP maintenance

muscle spindle, golgi tendon organ, reduces friction

nociceptors

pain

joint kinesthetic receptors

sensitive to joint angles and position

muscle spindles

sensitive to muscle length, sense of stretch

golgi tendon organ

sensitive to tension in tendon, sense strength of contraction, don’t activate before exercise

motor divison (efferent)

transmit information from brain to periphery

autonomic

regulates involuntary activity

-smooth muscle, cardiac muscle

-sympathetic, parasympathetic

somatic

stimulates skeletal muscle

sympathetic stimulation

heart rate, BP, blood flow to muscles, airway diamter increased, increased metabolic rate, glucose levels, FFA levels, decreased activity of glands and muscles, vasoconstriction in kidneys, decreased urine

Parasympathetic

rest and digest, conservation of energy, digestion, urination, heart rate, dia

sensory motor integration

process of communication and interaction between sensory and motor systems

specialized intrafusal muscle fibers

innervated by y motor neurons, sensory for muscle fiber stretch

Golgi tendon organs

inhibits agonists, excite antagonists

stress/exercise response

glycogenolysis, gluconeogensis, inhibition of glycogenesis, glycolysis

normal glucose concentrations

100 mL

glycogenesis is inhibition because of

the deactivation of insulin

total blood glucose blood

5 grams, 20 kcal

total blood volume

5 L

glucagon promotes

gluconeogenesis

carbon precursors are

lactate, pyruvate, glycerol, alanine

exercise above 60%, epinephrine increases which increases

glycogen breakdown and increase in blood glucose

secondary exercise response

catecholamines, GH

attempt to preserve glucose

mobilization of additional fuel sources (TAGS, fatty acids, lactate, leucine)

steroid hormones are derived from

cholesterol

steroid hormones are soluble in

lipids, diffuse through membranes

steroid hormones are secreted by what glands

adrenal cortex, ovaries, testes, placenta

non steroid hormones are divided into two groups

protein/peptide hormones and amino acid derived hormones

non steroid hormones are

not lipid soluble, can’t cross membranes

peptide/protein hormones are from

pancreas, hypothalamus, pituitary gland

amino acid derived hormones are from

thyroid, adrenal medulla

high level of downstream

decreases secretion, negative feedback

hormones are secreted

pulsatile, plasma concentrations can fluctuate

downregulation

decreased number of receptors, high plasma concentration= densenitization

up regulation

increased number of receptors high plasma concentration= sensitization

hormone-receptor complex

hormone binds to specific receptor

affect permeability of target cell membrane

insulin increases permeability to glucose

activate an enzyme or enzyme system

epinephrine- glycogenolysis causes activation of cAMP

GH- protein synthesis

activate genetic apparatus to manufacture intracellular proteins or other substances

polypeptide hormones (non steroid hormones) receptors are located on

cell surface

steroid hormones receptors are located

through the membrane, cytoplasm or nucleus

non steroid hormones use

second messengers

common second messengers

cyclic adenosine monophosphate (cAMP), cyclic guanine monophosphate (cGMP), inositol triphosphate (IP3), diacylglycerol (DAG)

Pituitary gland is attached to and has 3 lobes

inferior hypothalamus, anterior, intermediate, posterior

what effect does exercise have on the pituitary glands

increases secretion

Growth Hormone is released from

anterior pituitary gland

growth hormone effects

anabolic, builds tissues, organs, muscle hypertrophy, stimulates fat metabolism

Where releases TSH (thyrotropin)?

anterior pituitary gland, then it travels to thyroid to release T3 and T4

exercise has what effect on TSH

increase of protein synthesis, increase size and number of mitochondria, promote rapid cellular uptake of glucose, enhance glycolysis and gluconeogenesis, enhance lipid mobilization, increase FFA availability

what are the catecholamines

epinephrine and norepinephrine