C3 Tissue response

Question 1

Describe the main changes in body fight flight

Answer 1

Sympathetic nervous system activated
Vasodilation blood vessels ↑ blood to organs & tissues
↑ HR / contraction force
Breakdown glucagon stores need E = ↑ blood sugar
Blood diverted to skeletal muscle & brain
Dry mouth & clammy skin (-ve effect as body not concerned w/ digestion)

Question 2

what are the effects of B1, B2, B3, a1 & a2 on smooth muscle & heart & GI tract

Answer 2

smooth muscle
B1 - decrease intestinal motility
B2 - vasodilation/ bronchodilation/ uterus relaxation
a1 - contraction all smooth muscle + mydriasis
relaxation GI tract
a2 - contraction of blood vessels only

heart
B1 - increase force & rate of contraction
B2 - no major effects

B3 - lipolysis in fat cells

platelets
a2 aggregation

neurons
a2 hyperpolarization

Question 3

Name a1 vascular effects

Answer 3

vasoconstriction: decrease blood flow to skin, kidneys, gut & liver
((less effect on blood flow to heart, lungs, Brain, skeletal muscle))

Question 4

where are a1 & a2 located on artery

Answer 4

a1 receptor close to release site of NA. activated by neuronal & circulating NA
a2 distant from Na release site. Activated by circulating NA (normally associated w/ more severe FFF)

Question 5

describe a2 neuronal effects

Answer 5

a2R activated Gi/o = increase in K efflux –> hyperpolarization
1. decrease response to excitatory synaptic input
2. decrease in spontaneous action potentials
BOTH = decrease nerve activity

Question 6

what inhibits NTS

Answer 6

NA

NTS: nucleus tractus solitarus. located: brain - controls basic functions

Question 7

describe the effect of a2 on BP

Answer 7

a2 lowers BP effects on brain & periphery nerve terminals via -ve feedback:
stim of a2R = closure Ca channels –> lowers intracellular CA –> reduces NA release
(Na at a2 inhibits Ca & activates K)

Question 8

define +ve chronotropic & +ve inotropy and where they exhibited effects

Answer 8

effects of B1
+ve chronotropic (SA node) ↑ HR
+ve inotropy (cardiac muscle) ↑contraction
both = ↑ CO

Question 9

β1 receptor stimulation of kidney results in

Answer 9

release of renin from JGA cell in afferent arterioles
–> release Ang I & II (lungs) –> aldosterone release (adrenal cortex) –> decrease na & H2O excretion (kidney)
= increase BP

Question 10

β2 receptor stimulation of liver results in

Answer 10

glycogen phosphorylase converts glycogen to glucose –> TCA (skeletal muscle) –> E release = contraction