Physiology Exam 2

Front 1

Afferent division of nervous sytem

Back 1

input back to CNS

Front 2

Efferent division of nervous system

Back 2

input away from CNS

Front 3

Autonomic nervous system divisions

Back 3

Sympathetic (thoracolumbar)
Parasympathetic (craniosacral)
Enteric (gut brain)

Front 4

Somatic motor system events/structure

Back 4

1. CNS command
2. lower motor neuron
3. NMJ excitation/contraction coupling
4. skeletal muscle contraction
5. movement

Front 5

Autonomic system events/structure

Back 5

1. CNS command reflex to periphery
2. tonic control
3. preganglionic fiber
4. ganglia/postganglionic fiber
5. organ
6. response + or -

Front 6

Sympathetic Nervous system pre/post ganglionic lengths

Back 6

pre- short
post- long

Front 7

Parasympathetic nervous system pre/post ganglionic lengths

Back 7

pre-long
post-short

Front 8

Implications of dual innervations of target organs by PNS and SNS

Back 8

reciprocal effects- one inhibits while other stimulates - fine control of organ functions (heart rate and intestinal motility)
cooperative effects- promote same goal (salivary gland secretion and male sexual response)

Front 9

Neurotransmitters of PNS and SNS

Back 9

Acetylcholine (ACh) and Norepinephrine (NE)

Front 10

Acetylcholine-where

Back 10

cholinergic nerves.
all sympathetic and parasympathetic preganglionic nerves.
sympathetic postganglionic nerves innervating sweat glands in skin and some skeletal muscle blood vessels.
all parasympathetic postganglionic nerves.

Front 11

Norepinephrine

Back 11

adrenergic nerves.
most sympathetic postganglionic nerves.
adrenal medulla releases some into blood stream

Front 12

Epinephrine

Back 12

hormone of sympathetic nervous system.
released from adrenal medulla

Front 13

Adrenal medulla

Back 13

modified postganglionic neuron of sympathetic nervous system. releases EPI, NE, and dopamine (catecholamines).

Front 14

Parasympathetic neurotransmitters

Back 14

pre- ACh
post- ACh

Front 15

Sympathetic neurotransmitters

Back 15

pre- ACh
post- NE, ACh
adrenal medulla- EPI, NE, dopamine

Front 16

Acetylcholine synthesis/degradation/function

Back 16

synthesized from AcCoA + choline by choline acetyl transferase (Chat).
stored in vesicles which are released when AP increases Ca2+ entry into nerve ending
binds to receptor and broken down in synaptic cleft by acetylcholinesterase (AChE).
AChE inhibitors used to treat glaucoma, increase GI motility, and myasthenia gravis.

Front 17

Norepinephrine synthesis/degradation (presynaptic and target cells)/diffusion

Back 17

tyrosine enters nerve terminal > DOPA > dopamine > NE
NE stored in vesicles complex with ATP and released when AP increases Ca2+ entry into nerve ending.
binds to receptor.
presynaptic: uptake by active pump mechanism (uptake-1) which is inhibited by cocaine and tricyclic antidepressants. NE metabolized by enzyme MAO
target cells: uptake-2 pump that is not sensitive to cocaine. NE metabolized by enzyme COMT.
diffusion-detectable in plasma
(also metabolized in liver)

Front 18

Cholinergic receptors (4)

Back 18

muscarinic M1-increase intracellular Ca2+
muscarinic M2-inhibit adenylyl cyclase
muscarinic M3- increase intracellular Ca2+
nicotinic Nn-open Na+ and K+ channels, depolarization

Front 19

Adrenergic receptors (5)

Back 19

a1- increase intracellular Ca2+
a2- decrease cAMP
b1- increase cAMP
b2- increase cAMP
b3- increase NO (nitric oxide)

Front 20

Dopaminergic receptors (2 groups)

Back 20

D1,D5- increase cAMP
D2,D3,D,4- decrease cAMP

Front 21

Tonic activity of autonomic nervous system

Back 21

active under resting conditions
fine control-increase or decrease
SNS and PNS tonically acticve to most organs they innervate

Front 22

Reflex activity of autonomic nervous system

Back 22

response to change in environment (may not require cortical processing)
many basic reflexes modulated by other inputs to CNS or by higher brain sensor

Front 23

Parasympathetic nervous system - Rest & Digest - examples (7)

Back 23

constrict pupils,
increase watery saliva
enhance GI GU emptying
stimulate release of insulin and enhance storage of excess glucose as fat and glycogen
slow heart rate
constrict airways
open resistance vessels of coronary circuit

Front 24

Sympathetic nervous system - Fight or Flight - examples (8)

Back 24

dilate pupil
increase thick viscous salive
decrease intestinal motility
stimulate hepatic glycogenolysis and inhibit insulin release
increase heart rate and cardiac contractility
dilate bronchial smooth muscle
alter blood flow by changing vasoconstriction of blood vessels
sweating

Front 25

Heart - reciprocal effects of PNS/SNS

Back 25

Heart Rate:
SNS (NE or EPI)- increase pacemaker rate, increase heart rate
PNS (ACh)- decrease pacemaker rate, decrease heart rate
Contractility:
SNS (NE or EPI)- increase force of ventricular contraction

Front 26

Lungs - reciprocal effects of PNS/SNS

Back 26

bronchiolar smooth muscle:
SNS (NE)- relax
PNS (ACh)- constrict and increase glandular secretions

Front 27

Salivary gland- cooperative effects of PNS/SNS

Back 27

SNS-viscous secretion
PNS- watery secretion

Front 28

Lacrimal glands- cooperative effects of PNS/SNS

Back 28

SNS/PNS both cause secretion

Front 29

Sexual response- cooperative effects of PNS/SNS

Back 29

PNS-erection
SNS-ejactulation
"point and shoot"

Front 30

Autonomic centers in hypothalamus and brainstem- function

Back 30

visceral reflex control

Front 31

Smooth muscle contraction functions

Back 31

propel contents through hollow organ or tube
maintain pressure against contents within hollow organ
regulate internal flow of contents by changing tube diameter

Front 32

Smooth muscle cell description

Back 32

spindle-shaped cells with single nucleus, usually arranged in sheets within muscle, dense bodies containing same protein found in Z-lines, single-unit/multi-unit. less developed sarcoplasmic reticulum but it is in contact with plsma membrane. caveolae-membrane lipid rafts for extracellular communication.

Front 33

Single-unit (visceral) smooth muscle

Back 33

gap junctions conduct Na+ and Ca2+. cells funcation as syncytium.
myogenic (self-excitable)
fibers contract as single unit.
contraction slow and energy efficient

Front 34

Filaments in smooth muscle

Back 34

thick myosin-longer than in skeletal
thin actin- no troponin
intermediate size-form part of cytoskeletal framework that supports cell shape and hold dense bodies in place.
diamond shaped lattice.
15:1 ratio
resting length is shorter than skeletal muscle

Front 35

Smooth muscle innervation

Back 35

variscosities

Front 36

Multi-unit smooth muscle-description

Back 36

neurogenic (nerve-produced)
discrete units that function independently of eachother
units must be separately stimulated to contract

Front 37

Multi-unit smooth muscle- where

Back 37

walls of large blood vessels
small airways to lungs
muscle of eye that adjusts lens
iris
base of hair follicles (goose bumps)

Front 38

Single-unit smooth muscle- where

Back 38

GI
bladder
small blood vessels
uterus
ureter

Front 39

Electrophysiology of smooth muscle cells

Back 39

RMP- variable -65mV to -45mV
AP- Ca2+ dependent
most multi-unit do not fire APs
spontaneous depolarization of single unit: pacemaker potential, slowwave potential

Front 40

Pacemaker potential of single-unit smooth muscle cells

Back 40

membrane potential gradually depolarizes until it reaches threshold for firing single AP

Front 41

Slow wave potential of single-unit smooth muscle cells

Back 41

membrane potential alternately depolarizes and hyperpolarizes. when threshhold is reached, cell fires a burst of APs

Front 42

Smooth muscle contraction regulation

Back 42

regulation of crossbridge cycling occurs on myosin filament.
light chain proteins attach to heads of myosin

Front 43

Smooth muscle excitation-contraction coupling

Back 43

increase in cytosolic Ca2+
Ca2+ binds to calmodulin in cytosol
Ca2+-calmodulin complex binds to and activates enzyme myosin light-chain kinase (MLCK)
MLCK uses ATP to phosphorylate myosin cross bridges
Phosphorylated myosin cross-bridges bind to actin
Cycling produces tension and shortening
Power stroke- release of ADP-Pi from myosin head
cross-bridge detachment requires ATP

Front 44

Smooth muscle contraction when P is removed when actin/myosin are bound

Back 44

myosin remains bound to actin
latch-bridge forms and detaches very slowly or not at all
tonic level of tension with little ATP consumption

Front 45

Smooth muscle contraction gradation

Back 45

increased Ca2+ causes increase in cross-bridges and therefore greater tension

Front 46

Mechanisms for increasing intracellular [Ca2+] in smooth muscle (4)

Back 46

voltage-gated Ca2+ channel (single-unit only)
ligand-gates Ca2+ channel
SERCA
Ip3 gated Ca2+ channel

Front 47

Types of smooth muscle contraction (3)

Back 47

basal tone
phasic contraction
tonic contraction

Front 48

Basal tone in smooth muscle

Back 48

low level of force in absence of extrinsic factors.
intrinsic property of smooth muscle.
cytosolic [Ca2+] sufficient to maintain low level of crossbridge cycling

Front 49

Phasic smooth muscle contraction- characteristic and where

Back 49

rapid production of force and subsequent rapid relaxation as [Ca2+] returns to basal levels
*GI tract and GU organs

Front 50

Tonic smooth muscle contraction- characteristic and where

Back 50

continuous production of force in presence of falling [Ca2+] that remain above basal levels. crossbridge cycling continues at low level.
*airways, blood vessels, GI

Front 51

Relaxation of smooth muscle

Back 51

decrease in cytosolic [Ca2+]
MLCK returns to inactive form
enzyme myosin phosphate removes phosphate from myosin
cross-bridge reattachment inhibited

Front 52

Mechanisms for decreasing intracellular [Ca2+] in smooth muscle (3)

Back 52

SR Ca2+ ATPase (SERCA)
Sarcolemmal Na+/Ca2+ exchanger
Sarcolemmal Ca2+ ATPase

Front 53

Main structural differences in cardiac muscle

Back 53

Many mitrochondria
Capillary
Increased % of connective tissue
Gap junctions
Intercolated disk

Front 54

Major types of cardiac cells (3)

Back 54

Contractile
Conductile
Pacemaker/Nodal

Front 55

Contractile cardiac cells

Back 55

ventricular and atrial.
contraction (pumping)
fast APs

Front 56

Conductile cardiac cells

Back 56

Purkinje.
rapid spread of electrical signal
fast APs

Front 57

Pacemaker (Nodal) cardiac cells

Back 57

SA and AV node
pacemaker activity
slow APs

Front 58

Phases of fast action potential in contractile and conductile/purkinje cells

Back 58

Phase 0: upstroke of AP, due to fast inward iNa+
Phase 1: early repolarization due to activation of some transient K+ channels (iKto)
Phase 2: plateau phase due to balance between iCa2+L and iK
Phase 3: repolarization due to iCa2+L turned off and increase in iK
Phase 4: resting potential, due to large iK1

Front 59

Absolute refractory period in cardiac muscle

Back 59

Na+ channels inactivated
extends from onset of Phase 0 to half-way through Phase 3 when membrane potential has reached ~-50mV

Front 60

Relative refractory period in cardiac muscle

Back 60

Na+ channels becoming activated again
halfway through Phase 3 to end of Phase 3 repolarization

Front 61

Action potentials of nodal cells

Back 61

maximum diastolic potential~-65mV to -55mV
Ca2+ dependent upstroke

Front 62

Pacemaker currents

Back 62

iF-funny current-inward mixed cation (Na+ and K+)
iCa2+T- transient inward
iCa2+L- long-lasting inward
iK+-delayed rectifier outward

Front 63

Excitation-contraction coupling in cardiac cells events

Back 63

1. Excitation-AP cause depolarizaton of membrane
2. Ca2+ channels open (L-type)
3. Ca2+ enters cell
4. Ca2+induced Ca2+ release (CICR) from SR
5. cytosolic Ca2+ levels increase
6. Ca2+ binds to troponin
7. crossbridge cycling
8. contraction

Front 64

Regulation of cardiac contraction

Back 64

alterations in fiber length
changes in contractility

Front 65

Length-tension relationship in cardiac muscle

Back 65

stretching cardiac muscle fibers (to a point) increases strength of contraction because it is though it isn't overlap of myosin/actin but the distance between them that affects force by affecting sensitivity to Ca2+

Front 66

Ca2+ and cardiac contractility

Back 66

modulation of L-type Ca2+ channels and the SR