Lecture Exam 2- Ch. 8 Flashcards
neurons that innervate skeletal muscle
- within the CNS
- Voluntary responses
somatic nervous system
innervates cardiac muscle, smooth muscle, exocrine/endocrine glands and adipose tissue/ viscera
- automatic/ involuntary
- subdivisions: parasympathetic, sympathetic, enteric
Autonomic nervous system
- No ganglia
- 1 neuron from CNS to effector
- Type of neuromuscular junction: specialized motor end plate
- Effect of nerve impulse on muscle: excitatory only
somatic motor
- cell bodies of postganglionic autonomic fibers located in paravertebral, prevertebral (collateral) and terminal ganglia
- 2 neurons from CNS to effector
- Type of (postganglionic & preganglionic)
- neuromuscular junction: no specialization of postsynaptic membrane
- Effect of nerve impulse on muscle: either excitatory or inhibitory
autonomic motor
- cell bodies of postganglionic autonomic fibers located in paravertebral, prevertebral (collateral) and terminal ganglia
- 2 neurons from CNS to effector
- Type of (postganglionic & preganglionic)
- neuromuscular junction: no specialization of postsynaptic membrane
- Effect of nerve impulse on muscle: either excitatory or inhibitory
autonomic motor
nerves innervate walls of the GI tract
enteric
one organ receiving sympathetic & parasympathetic input
Dual innervation
- decreases heart rate
- Relaxes bladder sphincter
Dual innervation: Parasympathetic
- Increases heart rate
- Dilates and constricts veins
- Contracts bladder sphincter
dual innervation: sympathetic
heart rate is controlled by
pacemaker cells
the sympathetic system prepares the body for intense physical activity in emergencies and stress (physically or mentally); the heart rate increases, blood glucose level rises, and blood is diverted to the skeletal muscles (away from the visceral organs and skin).
mass activation
the number of postsynaptic fibers on a single preganglionic fiber creates a synapse with
divergence
allows a neuron to receive input from many neurons in a network
convergence
the capacity of excited neurons to reduce the activity of their neighbors
Lateral inhibition
- release of norepinephrine from postganglionic neurons and the secretion of epinephrine from the adernal medulla
- heart rate, blood pressure increase
- blood increases to skeletal muscles, heart and brain
fight or flight
rest and digest
parasympathetic division
- releases ACh from post ganglionic neurons
- slows heart rate (decreases rate of pacemaker cells) and increases digestive activities
parasympathetic division
in parasympathetic divison there is no
mass activation
short postganglionic neurons in the PSNS allow for
local responses
short preganglionic in the SNS allow for lots of
divergence and convergence of information
sympathetic chain (column) of ganglia
Paravertebral ganglia
Postsynaptic membrane of:
- All autonomic ganglia
- All neuromuscular junctions
- Some CNS pathways
Depolarization → Excitation
Nicotinic ACh receptors (receptor for acetylcholine)
Produces parasympathetic nerve effects in the heart, smooth muscles, and glands
- Depolarization —(k+ channels closed)→ Excitation
– Causes smooth muscles of digestive tract to contract
G-protein-coupled receptors (receptors influence ion channels by means of G-proteins)
- Hyperpolarization —(k+ channels opened)→ Inhibition
– Produces slower heart rate
Muscarinic ACh receptors (receptor for acetylcholine)
