Lecture 16 Questions UNFINISHED

Question 1

What are the two branches of the efferent division of the nervous system?

Answer 1

1. Somatic Nervous System

2. Autonomic Nervous System

Question 2

how does afferent play a role?

Answer 2

afferent - sensory

the smooth muscle, cardiac muscle, & glands & effector organs are unconscious and sent to a branch of the afferent division called the visceral stimuli

• may or may not be aware of this (unconscious)
• it’s detected & sent back to the CNS & ultimately processed again
• Ex: not aware of min to min blood pressure, heart rate etc - unconscious

ASK??

Question 3

Do visceral effectors need the ANS to function? Give examples.

Answer 3

• Most visceral effectors do not need the ANS to function,
only to adjust their activity to match the body’s needs to
maintain homeostasis
– Heart rate for example.

Question 4

explain the two neuron chain in the ANS. Describe the similarities and
differences between the sympathetic and parasympathetic divisions using the
following words: preganglionic, postganglionic, short, long, preganglionic
receptors, postganglionic receptors, nicotinic, muscarinic, spinal cord, brainstem
Ach, NE..

Answer 4

Two-neuron chain

• Preganglionic fiber (synapses with cell body of second neuron)
• Postganglionic fiber (innervates effector organ or tissue)

Question 5

give at least two ways that the ANS regulation of adrenal medulla different from heart?

Answer 5

ASK?

Question 6

what is the vagus nerve? Where does it send sensory info? What happens next?

Answer 6

• Tenth cranial nerve
• “Wandering”
• Many branches
• Innervates all
organs except
adrenal medulla and
some parts of the
colon

1. Vagus nerve carries sensory information from most of
   the viscera. Many of these sensory afferents project
   topographically to Nucleus of the Solitary Tract
   (abbreviated NST or NTS) in the brainstem.
2. The sensory info is processed within the NTS.
   The NTS may also project axons to “higher” parts of the brain,
   hypothalamus and cortex
3. Vagus nerve carries efferent (parasympathetic)
   information to regulate/modulate organ function

Question 7

how many adrenoceptors are there?
Muscarinic receptors?
What second messenger systems do these receptors link to?
Are these receptors receptor channels or GPCR?

Answer 7

ASK!

Question 8

state why the effects of SNS or PNS on a type of tissue may be hard to predict? State the easiest way to figure out the effect.

Answer 8

ASK!

Question 9

explain the idea of dual innervation and antagonistic regulation. Are all targets regulated this way? Give examples

Answer 9

Most of your organs have dual innervation. Input from both SNS internal and PNS
• Not always balanced
– Digestive has much more PNS than SNS

Effects can be antagonistic or complimentary
• Antagonistic
– The heart is innervated by both
• SNS increases heart rate and force of contraction
• PNS decreases heart rate and force of contraction
– The iris innervated by both
• SNS innervates the pupillary dilator
• PNS innervates the pupillary constrictor
• Complimentary
– Activation of SNS and PNS produce similar results
• Salivary glands are innervated by both SNS and PNS
– Both increase saliva production, but different kinds of saliva » SNS stimulates mucus production
» PNS stimulates watery, enzyme rich saliva
• Male sexual response PNS responsible for erection, SNS responsible for ejaculation* (point and shoot)

?

Question 10

how is the synapse at the neuromuscular junction different from a synapse of the ANS?

Answer 10

like all other synapses:

(1) the motor neuron’s presynaptic axon terminal filled with synaptic vesicles & mitochondria
(2) the synaptic cleft
(3) the postsynaptic membrane of the skeletal muscle fiber

IN ADDITION, the NMJ includes extensions of Schwann cells that form a thin layer covering the top of the axon terminal