13

Question 1

what 2 ways do animals communicate

Answer 1

*chemical - using hormones
electrical - using neurones

Question 2

internal changes?

Answer 2

*Water potential
*Cell pH
*Glucose level
*Internal temp

Question 3

external changes

Answer 3

*Light
*External temp
*New or sudden sound
*Humidity

Question 4

why is coordination important?

Answer 4

organisms evolve and therefore certain cells may become specialised. The organism will need to coordinate these cells and systems to operate effectively.

Question 5

coordination example

Answer 5

RBC carries O2 but relies on stem cells for RBC reproduction as RBCs dont have nucleus. However, stem cells are unable to respire and produce RBCs w/o O2. Therefore RBCs and stem cells work in coordination.

Question 6

Homeostasis

Answer 6

The maintenance of relatively constant conditions in the body.

Question 7

homeostasis p2

Answer 7

communication and coordination allows us to maintain homeostasis

Question 8

cell signalling

Answer 8

*Neurotransmitters between neurones signal locally
*Hormones transfer signals across larger areas

Question 9

plants signalling

Answer 9

use hormones to respond to stimuli e.g growth toward light

Question 10

Neurones?

Answer 10

specialised cells that transmit electrical receptors

Question 11

synapse?

Answer 11

The gap between 2 nerve cells in which neurotransmitters are used to transfer the signal

Question 12

Reflex arc (refresher)

Answer 12

1 - stimulus
2 - receptor
3 - sensory neurone
4 - synapse
5 - relay neurone
6 - synapse
7 - motor neurone
8 - effector

Question 13

what do nerve cells do?

Answer 13

transmit impulses from relay or sensory neurones to effectors such as muscles or glands

Question 14

Sensory neurone

Answer 14

Transmits signals from sensory neurone to relay neurones, motor neurones and Brain

Question 15

Relay neurone

Answer 15

Transfer impulses between neurones
*also called interneuron

Question 16

Shwan cells

Answer 16

Produce layers of plasma membrane around the axon of some neurons

Question 17

myelinated neurones

Answer 17

conduct impulses much faster compared to unmyelinated.

Question 18

nodes of Ranvier -

Answer 18

gaps between myelin sheath
*allows node impulses to jump from one node to the next

Question 19

Central nervous system

Answer 19

Brain and spinal chord

Question 20

Peripheral nervous system

Answer 20

Everything else not in CNS

Question 21

Autonomic nervous system (under peripheral)

Answer 21

controls unconscious/ involuntary processes e.g heartbeat

Question 22

Somatic nervous system (under peripheral)

Answer 22

plays the role in voluntary movements

Question 23

sympathetic (under somatic)

Answer 23

Responsible for fight or flight e.g higher heart rate, more alert

Question 24

parasympathetic (under somatic)

Answer 24

responsible for rest and digest e.g lower heart rate and increased rates of digestion

Question 25

What are internal factors that an organism may respond to?

Answer 25

Blood glucose Internal temp Water potential Cell pH

Question 26

What are some external factors that an organism may respond to?

Answer 26

Humidity External temp Light intensity New or sudden sound

Question 27

Describe the cell body of a neurone?

Answer 27

Contains nucleus surrounded by cytoplasm. Many ER and mitochondria in cytoplasm used to produce neurotransmitters.

Question 28

What are dendrons?

Answer 28

Short extensions which come from cell body. The extensions divide into smaller branches called dendrites. Transmit electrical impulses towards cell body.

Question 29

What are axons?

Answer 29

Singular elongated nerve fibres. Transmit impulses Away from cell body. Cylindrical fibre with very narrow region of cytoplasm surrounded by plasma membrane.

Question 30

What are the different types of neurones?

Answer 30

Sensory, relay, motor.

Question 31

What do sensory neurones do? And do they have an abundance of axons and dendrons or not?

Answer 31

Transmit impulses from sensory receptor cell to relay neurone, motor neurone or brain. They have one dendron. Have one axon.

Question 32

What do relay neurones do? And do they have an abundance of axons and dendrons or not?

Answer 32

Transmit impulses between neurones. Have many short axons and dendrons.

Question 33

What do motor neurones do? And do they have an abundance of axons and dendrons or not?

Answer 33

Transmit impulses from a relay neurones or sensory neurone to an effector. Have one long axon and many short dendrites.

Question 34

What does the nervous response pathway look like?

Answer 34

Receptor -> sensory neurone -> relay neurone -> motor neurone -> effector cell

Question 35

Whats a transducer?

Answer 35

Something that changes one form of energy into another

Question 36

Where is cell body in motor neurone?

Answer 36

At end of cell

Question 37

What is the myelin sheath made of?

Answer 37

Schwann cells

Question 38

What does myelin sheath do?

Answer 38

Acts as insulating layer and allows neurones to conduct electrical impulses at much faster rate.

Question 39

What is a node of ranvier?

Answer 39

Small gap between each adjacent schwann cell. Electrical impulses jump from one node of ranvier to the next as it travels along the neurone.

Question 40

Why do electrical impulses need nodes of ranvier to move along a myelinated neurone?

Answer 40

As the myelin sheath is wraped so tightly around the neurone that it prevents the movement of ions across the neurone membranes and so the the action potential has to jump from one node to the next

Question 41

Can non myelinated neurones have schwann cells?

Answer 41

Yes but several neurones will be enshrouded by a loosely wrapped schwann cell.

Question 42

What are the two main features of sensory receptors?

Answer 42

- specific to a single type of stimulus - act as a transducer - they convert stimulus into a nerve impulse

Question 43

Whats an effector?

Answer 43

An organ that becomes active in response to a nerve impulse

Question 44

What are the 4 main sensory receptors in animals?

Answer 44

-mechanoreceptor - pressure and movement - pacinian corpuscle - skin -chemoreceptor - chemicals - olfactory receptor - nose -thermoreceptor - heat - end bulbs of Krause - tongue -photoreceptors - light - cone cell - eye

Question 45

What is a pacinian corpuscle?

Answer 45

Specific sensory receptor that detects mechanical pressure

Question 46

Where is pacinian corpuscle found?

Answer 46

Deep within skin and mainly around fingers and soles of feet

Question 47

How does pacinian corpuscle convert mechanical pressure to nervous impulse?

Answer 47

1) in resting state, the stretch-mediated sodium ion channels in sensory neurones membranes are too narrow to allow sodium ions to pass through them. This is resting potential. 2) when pressure is applied to pacinian corpuscle, it changes shape. This causes the membrane surrounding its neurone to stretch. 3) when the membrane stretches, thee sodium ion channels present widen. Sodium ions can now diffuse into neurone. 4) the influx of positive sodium ions changes the potential of the membrane - it becomes depolarised, resulting in generator potential. 5) in turn the generator potential creates action potential that passes along sensory neurone. The action potential will then be transmitted along neurones to CNS.