Mod 4. L32

Question 1

generalized vertebrate brain

Answer 1

divided into 3 main divisions :
- Hindbrain
- Midbrain
- Forebrain

Question 2

forebrain

Answer 2

telencephalon (cortex)
diencephalon (hypothalamus)

Question 3

midbrain

Answer 3

mesencephalon

Question 4

hindbrain

Answer 4

metencephalon (pons and cerebellum)
myelencephalon (medulla oblongata)

Question 5

spinal cord

Answer 5

part of the CNS serves to transmit nerve signals from the brain to the body and from sensory neurons in the PNS to the brain
it also coordinates a number of reflexes and pattern generators

Question 6

PNS peripheral nervous system and its divisions

Answer 6

has 2 divisions
1. sensory division
relays sensory info to CNS

2. motor division
   somatic and automatic nervous system

2.1 somatic = part of PNS under voluntary control
2.2 automatic = involuntary responses to regulate physiological responses (divided in 3 sections_

2.2.1 parasympathetic
2.2.2 sympathetic
2.2.3 enteric (we wont talk about this one)

Question 7

parasympathetic system

Answer 7

engaged under resting conditions

Question 8

sympathetic

Answer 8

engaged under stressful situations

Question 9

neuromuscular junction

Answer 9

the chemical signal between a motor neuron and a skeletal muscles

transmission at this junction involves Ca2+ and the neurotransmitter acetylcholine and leads to the depolarization of muscles

Question 10

neurotransmitter receptors (2 types)

Answer 10

ionotropic receptors
metabotropic receptors

Question 11

ionotropic receptors

Answer 11

form an ion channel pore. neurotransmitters bind to these receptors, causing a conformational change that allows ions to move through the pore. These are sometimes called ligand-gated ion channels

Question 12

metabotropic receptors

Answer 12

GPCR
indirectly linked with ion channels on the plasma membrane through signal transduction mechanisms

Question 13

chlorpyrifos

Answer 13

organophosphate insecticide used primarily to control foliage and soil-borne insect pests

it acts by inhibiting the action of acetylcholinesterase (enzyme degrading acetylcholine in the post-synaptic cleft)

it effects the insect by killing it through overstimulation (because the acetylcholine is never degraded) it always stimulates the muscle cell making it become ridgid over time and other negative effects

Question 14

Ivermectin

Answer 14

an anti-parasitic drug that is effective at killing internal parasites (eg parasitic worms)

the drug binds to ionotropic chloride channels that are common to invertebrate nerve and muscle cells

consequence: ivermectin hyperpolarizes and inhibits neurons, thereby paralyzing and killing the invertebrate
for example: prevents neurons controlling muscles for feeding to be activated

note: ivermectin is safe for mammals because it usually does not cross the blood-brain barrier and thus is unlikely to bind to other mammalian ligand-gated channels