Exam 3: Chapter 11 Flashcards
what are the two subtypes in the efferent division?
autonomic NS (glands, smooth muscle, cardiac muscle, adipose)
somatic NS (skeletal muscle)
what are the two subtypes in the autonomic NS?
sympathetic (fight or flight)
parasympathetic (rest & digest)
describe the preganglia for the sympathetic NS. What is the length, location, and what NT do they release?
-length: short
-location: thoracic & lumbar region of spinal cord
-release: ACh
describe the location of the autonomic ganglia for the sympathetic NS?
closer to the spinal cord
describe the postganglia for the sympathetic NS. What is the length and what NT do they release?
length: long
release: NE
describe the preganglia for the parasympathetic NS. What is the length, location, and what NT do they release?
length: long
location: brainstem & sacral regions of SC
release: ACh
describe the location of the autonomic ganglia for the parasympathetic NS?
closer to the effectors
describe the postganglia for the parasympathetic NS. What is the length and what NT do they release?
length: short
release: ACh
what type of receptors do the preganglia use for both the sympathetic and parasympathetic NS?
cholinergic
-bind to nicotinic receptors, N(N)
-ionotropic (ligand-gated)
what type of receptors do the postganglia use for both the sympathetic and parasympathetic NS?
sympathetic: adrenergic, bind to alpha and beta receptors
parasympathetic: cholinergic, bind to muscarinic receptors
-metabotropic (GPCR)
what is dual innervation?
organ is receiving info from both the sympathetic and parasympathetic NS in an antagonistic control
-sym: increases HR
-parasym: decreases HR
what are the three exceptions to dual innervation?
-sweat glands (SYMP)
-adrenal medulla (SYMP)
-blood vessels (SYMP): has different receptors for different effects
what is cooperation?
the symp and parasymp working together instead of against eachother
-only in GENITALS
what is the neuroeffector junction?
synapse b/w postgang cell & effector
-end in varicosities (instead of an axon terminal)
what are varicosities?
swellings that contain and release NT (NE, ACh)
-makes the NT, no axonal transport
what are the steps at the neuroeffector junction?
- AP arrives at varicosity
- depolarization opens voltage-gated Ca2+ channels
- Ca2+ triggers exocytosis of vesicles
- NT binds to receptor on target
- activation of receptor stops when NT diffuses out of synapse, reuptaked by nearby cells, or broken down by enzymes
what two types of enzymes break down NTs at the neuroeffector junction?
MAO: breaks down NE
acetylcholinesterase: breaks down ACh
-both work as indirect antagonists
what are the two alpha receptors? what are each used for?
alpha1: majority
alpha2: digestive tract, insulin secretion
what are the two beta receptors? what are each used for?
beta1: heart (equal sensitivity to E & NE)
beta2: bronchioles (more sensitive to E than NE)
whats special about the adrenal medulla?
type of chromaffin cell that lacks axons and secretes E directly into the blood
-neural tissue with no postganglia!
what is a direct agonist and antagonist?
combines with target receptor to mimic or block NT action
what is an indirect agonist and antagonist?
alters secretion, reuptake, or degradation of NT
HEART
symp (beta1): increase HR, increase force of contraction
parasymp: decrease HR
BLOOD VESSELS
symp (alpha & beta2)
-alpha = vasoconstriction
-beta2= skeletal muscle dilation
NO PARASYMP
BRONCHIOLES
symp (beta2): dilation
parasymp: constriction
DIGESTIVE TRACT MOTILITY & SECRETIONS
symp (alpha 2): decrease tract motility, decrease secretions
parasymp: increase tract motility & secretions
BLADDER
symp (alpha1): retention, relax
parasymp: constrict, empty
PUPIL
symp (alpha1): dialation
parasymp: constriction
CILIARY MUSCLE (lens)
symp (alpha1): relax, flat
parasymp: contracted, round
SWEAT GLANDS
symp (alpha1): increase secretion
NO PARASYMP
ADIPOSE TISSUE
symp (alpha): breakdown tissue, increase FA release
NO PARASYMP
ADRENAL MEDULLA
symp (no receptor): secrete E, increase fight or flight
NO PARASYMP
INSULIN SECRETION
symp (alpha2): decrease secretion
parasymp: increase secretion
GENITALS
symp (alpha1): orgasm, ejaculation
parasymp: erection
whats different about the somatic NS compared to the autonomic NS?
only 1 neuron b/w CNS and skeletal muscle
what is the neuromuscular junction?
synapse b/w somatic motor neuron and muscle fiber
what is the motor end plate?
folded region on muscle fiber that has ACh receptors
-uses nicotinic receptors N(M)
steps of the neuromuscular junction
- AP reaches terminal to open voltage-gated Ca2+ channels
- ACh released from neuron
- ACh moves across synapse and binds N(M) receptor
- receptor opens ligand-gated ion channels
- Na+ & K+ entry lead to a depolarization in muscle cell (NET Na+)
- APs sent along muscle cell
- contraction
