lecture 12

Question 1

homeostasis maintained via a balance between

Answer 1

ANS, endocrine, and behavioral systems

Question 2

the homeostatic control centers are

Answer 2

hypothalamus, pons, and medulla (brainstem)
- reponses can be autonomic, endocrine (hormones), and behavioural (hungry—>eat some food)

Question 3

name one autonomic function that can occur without brain input

Answer 3

urination when you’re a baby or erectile function

Question 4

parasympathetic

Answer 4

rest and digest

Question 5

sympathetic

Answer 5

fight or flight

Question 6

List an example where sympathetic and parasympathetic can be excitatory or inhibitory

Answer 6

1. Example: Heart rate
   parasympathetic: slows heart rate
   sympathetic: increases heart rate and force of contraction
2. Example: Gastrointestinal tract
   parasympathetic: promotes digestion
   sympathetic: halts/stops digestion

Question 7

most organs are under ____________ except _________

Answer 7

antagonistic control, blood vessels (only sympathetic)

Question 8

Sympathetic:
1. Origin in the CNS (where the cell body of N1 and N2)
2. Ganglion location
3. Pathways

Answer 8

1. preganglionic neuron —> in thoracolumbar segment
   postganglionic neuron –> in sympathetic ganglia
2. Sympathetic ganglia
3. short preganglionic
   long postganglionic

Question 9

parasympathetic:
1. Origin in the CNS (where the cell body of N1 and N2)
2. Ganglion location
3. Pathways

Answer 9

1. preganglionic neuron –> in brainstem and sacral segments
   postganglionic neuron–> near target
2. near or in the wall of the target organ
3. Long preganglionic
   short postganglionic

Question 10

autonomic synapse

Answer 10

where the preganglionic neuron meets the postganglionic neuron and tells it to do smt

–> it will do that by spitting out neurotransmitters ALWAYS acetylcholine (ACH)

Question 11

Name a few similarities between the sympathetic and parasympathetic pathways

Answer 11

1. both have acetylcholine-gated channels
2. both are permeable to Na+ and K+

Question 12

Name the differences between the sympathetic and parasympathetic pathways

Answer 12

Sympathetic pathway: postganglionic neuron releases norepinephrine neurotransmitter
- GPCR: adrenergic receptor

parasympathetic pathway: postganglionic neuron realeases acetylcholine neurtransmitter
- GPCR: muscarinic receptor

Question 13

adrenal medulla

Answer 13

• secretes epinephrine
• is a secret pathway with postganglionic neurons that are chromaffin cells
• secret because preganglionic neurons projects all the way to the adrenal gland

Question 14

norepinephrine cycle at sympathetic varicosity

Answer 14

1. action potential arrives at varicosity
2. depolarization opens voltage-gated Ca2+ channels
3. entry of calcium triggers exocytosis of synaptic vesicles
4. NE binds to adrenergic receptor on target
5. receptor activation ceases when NE diffuses away from synapse
6. NE is removed from synapse
7. NE is taken back for reuse or metabolized