Weeks 1-2 (BMR)

Question 1

What is the functional unit of the nervous system?

Answer 1

A Neuron (nerve cell)

Question 2

What is a glial cell?

Answer 2

Any of the cells in the nervous system that help support, connect and protect the neurons

Question 3

What is matrix?

Answer 3

the extracellular components that give structural support to everything in the nervous system

Question 4

What are the 2 types of signaling in the nervous system?

Answer 4

1. Electrical signals (propagated in a single neuron).
2. Chemical signals (between a neuron and another cell)

Question 5

What are the chemical ligands used in the nervous system?

Answer 5

Neurotransmitters (NT)

Question 6

Summarize the role of Ca++ in NT release

Answer 6

Depolarisation of the axon terminal activates voltage-gated Ca++ channels.

Ca++ enters the cell from the synapse & triggers exocytosis of synaptic vesicles.

Question 7

What are the ionic concentrations around the cell membrane at rest?

Answer 7

high [Na+] extracellular
high [K+] intracellular

Question 8

What happens at the neuron membrane when it receives either an excitatory or inhibitory stimulus?

Answer 8

If excitatory response, Na++ enters the cell, the potential moves toward 0mv = depolarisation.

If inhibitory response, e.g. Cl- allowed into the cell. membrane potential becomes more negative (hyperpolarisation)

Question 9

Briefly describe summation

Answer 9

excitatory/inhibitory responses are not the result of a single binding event, but rather thousands at once -a combination of depolarizing and hyperpolarizing events.

If there are more depolarising events, the cell will approach the threshold value which allows an electrical signal to be carried within the neuron (action potential).

Question 10

Describe the different involvement of chemically-gated and voltage-gated ion channels in generation of an action potential

Answer 10

chemically-gates channels are responsible for the initial, slower change in voltage -> enough to reach the potential threshold.

When the threshold is reached, the voltage-gates channels are then responsible for the fast & significant change required for the action potential.

Question 11

Describe the major event at each point in the action potential

Answer 11

Question 12

What are the 2 major divisions of the nervous system?

Answer 12

Central Nervous System & Peripheral Nervous System

Question 13

What are afferent and efferent CNS signals

Answer 13

Afferent - sensory - towards CNS

Efferent - motor - away from CNS

Question 14

Describe the 2 divisions of the efferent PNS?

Answer 14

Somatic = conscious, voluntary signals that target skeletal muscles

Autonomic = reflexive control that targets smooth & cardiac muscles, glands & adipose tissue

Question 15

Describe the 2 major subdivisions of the Autonomic Nervous System

Answer 15

Parasympathetic = “rest & digest”, stimulating GIT etc. Effector is ACh

Sympathetic = Fight, Flight, Freeze, Fuck - stress response. Effector NT is NE or Epinephine (uses ACh between neurons)

Question 16

The following physiological effects are suggestive of which division of the ANS?
-pupil dilation
-increased heart rate
-inhibits digestions
-relaxes airways

Answer 16

Sympathetic

Question 17

The following physiological effects are suggestive of which division of the ANS?
-pupil constricts
-decreased heart rate
-constrict airways
-increase bile secretion & GIT motility
-pancreas enzyme release

Answer 17

Parasympathetic

Question 18

Contrast the origin & structure of the sympathetic & parasympathetic nervous systems

Answer 18

Origin in CNS: Sympathetic from Thoracic & Lumbar segments. Parasympathetic from brainstem & sacral segments.

Ganglion location: Sympathetic ganglia chain close to the spinal cord. Parasympathetic ganglia close to or on target tissue.

Pathways: Sympathetic - short preganglionic & long postganglionic neurons. Parasympathetic - long preganglionic & short postganglionic neurons

Question 19

What are the 3 interdependent components of homeostatic control mechanisms? (and a summary of their function)

Answer 19

1. Receptor - detects change
2. Integrating Centre - part of CNS, makes sense of the incoming signal from PNS
3. Effector/Motor - allows response to be carried out to maintain homeostasis

Question 20

What are 2 types of skeletal muscle reflex pathways?

Answer 20

Monosynaptic reflex:
Afferent sensory neuron synapses directly with efferent motor neuron (mono = 1 synapse)

Polysynaptic reflex:
Multiple synapses between sensory & efferent neuron, can have further input from CNS. Allows modification of reflex (poly = >1 synapse)