nervous 1

Question 1

what is the simpilest form of nervous sytem

Answer 1

nerve nets, present in most animals

Question 2

what type of nervous sytem do vertebrates have

Answer 2

nerve plexus

Question 3

what is the diffrence between the central and periphiral nervous system

Answer 3

central are the brain and the spinal chord only. the peripherial system is the motor neuron and nerve fibers

Question 4

what is the somatic nervous sytem responsible for

Answer 4

controls the volantary movments

Question 5

what is the autonomic system resposible for

Answer 5

Control involantary responses, these include the parasympathetic and sympatheic system

Question 6

what is the parasympatheic nervous system responsible for

Answer 6

‘fight or fligh’

Question 7

what is the sympatheic nervous system responsible for

Answer 7

‘rest and digest’

Question 8

descibe the structure of a neuron cell

Answer 8

The nucleus lies inside of the dendrites (signal recivers) and cell body, then the axon, which is sometimes surronded by a mylin sheath once past the axon hilock. finally the axon terminal releases the signal.

Question 9

list the four structural types of neuron cells and define them

Answer 9

unipolar - only one extention
bipolar - two diffrent process that extend in opposite direction
pseudounipolar - only a sensory neuron
multipolar - possess a single axon with plently of dendrites, this allows for many differing connecting neuons.

Question 10

what are the three functional classification of neurons

Answer 10

sensory
motor
interneuron

Question 11

what are neuroglia

Answer 11

glial cells
- occupy half of the volume of the brain they serve as connective tissue in the CNS. they maintain the ECF enviroment surronding the neurons to modulate synaptic function. these arec rucial to memory and learning.

Question 12

what are Astrocytes

Answer 12

apart of the CNS they support neurons in development, repair ect.

Question 13

what are oligodendrocytes

Answer 13

they form the myelin sheath

Question 14

what are ependymal

Answer 14

they form cerebrospinal fluid

Question 15

define microglia

Answer 15

they provide an immune system for the CNS

Question 16

define polarisation

Answer 16

charges are separated across the plasma membrane

Question 17

define depolarization

Answer 17

Membrane is less negative as there is a decrease isn potential (+30 to +40 mV)

Question 18

define replarization

Answer 18

Membrane returns to resting potential after being depolarized (-70mv)

Question 19

define hyperpolarization

Answer 19

membrane is more negative than the resting potential (-80mv)

Question 20

how is the membrane conentration impacted by the action potential

Answer 20

When the action potential is reached by the chemical messages arriving at the dendrites the ion channels/gates open and the ion can move and there is an influx of Na+ via rapid diffusion. This changes the membrane polarity to depolarization.

Question 21

how is the membrane conentration maintained

Answer 21

Na+/K+pump which ensures that for every 3 Na leaving the membrane 2 K enter the cell.

Question 22

give a description of action potentials

Answer 22

Occurs due to ion movement. The action potentials are brief, rapid and occur when the threshold potential is reached, otherwise no reaction will happen, there are no weak potential, only all or nothing.

Question 23

what phases does the membrane potential undergo when given ample ions (ation potential)

Answer 23

1. polarisation
2. action potential initiates depolarization
3. repolarisation
4. hyperpolarization

Question 24

what impactes the rate of impulses

Answer 24

axon diameter (larger is faster due to lack of resistance)
Presence of a myelin sheath

Question 25

what are the types of propagate and describe them

Answer 25

1. Continguous conduction
   - neurotransmission of action potentials along a bear fibre such as parts in the CNS.
2. Saltatory conduction
   - the current jumps from each node to the next due to the myelinated sheaths as they are fatty insulators and cannot conduct electricity. This is significantly faster.

Question 26

what are the nodes of ranvier

Answer 26

exposed regions between the myelin sheaths of which are about 1 mm and contain a high concentration of Na+ channels which are voltage gated.

Question 27

What is released from the axon terminal?

Answer 27

Acteylcholine