week 3

Question 1

Antigen

Answer 1

capable of introducing an immune response

anything foreign to the host

Question 2

Body defences (list 2)

Answer 2

non-specific

specific

Question 3

Non-specific defences

Answer 3

general defence/ attack on all antigens
first and second line defences
react the same each time

Question 4

Specific defences

Answer 4

specialist/ targeted defence against one type of antigen

third line defences

Question 5

First line defences

Answer 5

keep invaders out via chemical and physical barriers

skin - epidermis, sebum + sweat
mucous membranes - mucous, hairs + cillia
fluids - tears, saliva, nasal secretions + urine
defecation - vomiting, coughing + sneezing

Question 6

Second line defences

Answer 6

act once microbes have entered the body

antimicrobial chemicals
phagocytes
natural killer cells
inflammation
fever

Question 7

Antimicrobial chemicals

Answer 7

is an agent that kills microorganisms or stops their growth

Question 8

Phagocytes

Answer 8

attracted to the affected site by chemotaxis, destroy bugs and clean up dead tissues

Question 9

Natural killer cells

Answer 9

immune surveillance- targets abnormal cells

Question 10

Inflammation

Answer 10

the bodies response to damages cells, destroys and removes antigens, cleans up dead tissue + debris

Question 11

Fever

Answer 11

systemic response

temp increases to kill of bugs
higher metabolic rate

Question 12

Third line defences

Answer 12

develops on exposure to a particular antigen

uses B + T lymphocytes made in bone marrow

Question 13

B and T cells (where they mature + type of immunity)

Answer 13

B cells -> mature in bone marrow
T cells -> mature in thymus

T cells are involved in cell-mediated immunity
B cells are primarily responsible for humoral immunity

Question 14

Functions of the nervous system (3 components)

Answer 14

sensory - knows whats happening
integrative - makes decisions
motor - does something about it

Question 15

Two parts of the nervous system

Answer 15

central nervous system (CNS)
- brain + spinal cord
peripheral nervous system (PNS)
- all nervous tissue outside the CNS

Question 16

PNS divisions (2 parts)

Answer 16

afferent (sensory information)

efferent (motor commands)

Question 17

Afferent (sensory)

Answer 17

brings sensory information to the CNS from the receptors situated in peripheral tissues + organs

Question 18

Efferent (motor) 2 sub categories

Answer 18

somatic nervous system (SNS)
     - controls skeletal muscle movement
     - involuntary + voluntary
autonomic nervous system (ANS)
     - parasympathetic (rest and digest) + sympathetic (fight or flight)
     - controls subconscious actions

Question 19

Neural tissue (2 parts)

Answer 19

neurons - cells that send + receive signals

neuroglia (glial cells) - cells that support + protect neurons

Question 20

Neurons and synapse elements (cell body, dendrite, axon, axon terminal, synapse)

Answer 20

cell body

• nucleus
• organelles

dendrites

• highly branches
• receive input from other neurons and take it to cell body

axon
- single long process
carries electrical signals (action potential) away from cell body to other neurons or effectors

axon terminals

• some enlarge -> synaptic end bulbs
• synaptic vesicles release neurotransmitters

synapes
- structure that allows a neuron to communicate with another cell
- pre-synaptic: neuron that sends message
- post-synaptic: neuron that receives message
- synaptic cleft: the small gap that separates the pre-
synaptic and post-synaptic membrane

Question 21

Neurotransmitters

Answer 21

a chemical substance which is released at the end of a nerve fibre by the arrival of a nerve impulse and, by diffusing across the synapse or junction, effects the transfer of the impulse to another nerve fibre, a muscle fibre, or some other structure.

Question 22

Nerve fibres

Answer 22

the axon of a neuron
axons run together
- CNS: tract
- PNS: nerve

Question 23

Neuronal cell clumps (in the CNS + PNS)

Answer 23

CNS -> nucleus

PNS -> ganglion

Question 24

Myelin sheath

Answer 24

made by glial cells
fatty white sheath around axons
increase speed of transmission

Question 25

White + grey matter

Answer 25

white matter - myelinated nerve fibres | grey matter - un-myelinated cell bodies and dendrites

Question 26

Resting membrane potential

Answer 26

ECF + ICF differ in ionic composition - high concentration of K+ inside - high concentration of Na+ outside

Question 27

Na+/K+ Exchanger

Answer 27

- Active transport - uses ATP - Transports - 2 K+ into the cell - 3 Na+ out of the cell

Question 28

Action potential

Answer 28

the membrane gets less negative and then returns to the resting level -> action potential 1. depolarisation (inside cell becomes less negative) - for a short time the cell becomes (+) 2. repolarisation (inside of the cell is becoming more negative) 3. hyperpolarisation (it becomes more negative than at rest) 4. resting membrane potential

Question 29

Depolarisation

Answer 29

Na+ ions enter the cell through voltage-gate Na+ channels and make the cell become less negative

Question 30

Repolarisation

Answer 30

K+ ions leave the cell through voltage-gated K+ channels and the cell becomes more negative

Question 31

Hyperpolarisation

Answer 31

too many K+ ions leave the cell and cell become more negative than at rest

Question 32

Refractory periods

Answer 32

absolute refractory period - no new action potential can be evoked relative refractory period - new action potential can be evokes (requires a very strong stimulus)

Question 33

Synapes/ neurotransmission process

Answer 33

- action potential travels along axon and reaches the pre-synpatic terminal - Ca+ channels open - Ca+ enters - neurotransmission chemical (acetylcholine) - Ca+ and the neurotransmission chemical form balls - Neurotransmission chemicals diffuses across the synaptic cleft - the neurotransmission chemical binds to the receptor (ion channels) - ion channels open - cations such as sodium flow into the post-synapetic terminal - if the sodium generates a big enough depolarisation the action potential continues along the next axon

Question 34

Label the neuron

Answer 34

``` cell body nucleus dendrites axon terminal axon action potential ```