Response To Stimuli - Nerves And Hormones

Question 1

What is a taxis?

Answer 1

A taxis is a simple response whose direction is determined by the direction of the stimulus.

Question 2

What is Positive taxis??

Answer 2

Movement towards a stimulus

Question 3

What is negative taxis?

Answer 3

Movement away from a stimulus!!

Question 4

What is tropism?

Answer 4

The growth of part if a plant in response to a directional stimulus.

Question 5

What is positive tropism ?

Answer 5

Growing towards the stimulus in response

Question 6

What is negative tropism?

Answer 6

Growing away from the direction if the stimulus in a negative response

Question 7

Three types of tropism…

Answer 7

Phototropism
Geotropism
Hydrotropism

Question 8

Central nervous system is made up of…

Answer 8

The brain and the spinal cord

Question 9

Peripheral nervous system is made up of…

Answer 9

Pairs of nerves that originate from either the brain or the spinal cord.

(The nerves in the systems)

Question 10

Peripheral nervous system is divided Into…..

Answer 10

Sensory neurones & motor neurones

Question 11

The motor nervous system can be subdivided into….

Answer 11

Voluntary nervous system &

Autonomic nervous system

Question 12

Rod cells - frequency in the retina?

Answer 12

More numerous !!

Question 13

Cone cells - frequency in the retina…

Answer 13

Less numerous!!

Question 14

Rod cells - shape and pigment ?

Answer 14

Rod shaped

Rhodopsin

Question 15

Cone cells - shape and pigment ?

Answer 15

Cone shaped

Iodopsin - this pigment occurs in 3 forms!!

Question 16

Rod cell pigment properties (rhodopsin) ??

Answer 16

Very sensitive to light and responds to low light intensities. But is unable to distinguish colour (monochromatic)

Question 17

Come cells - pigment properties (iodopsin) ??

Answer 17

Sensitive to only high light intensities and able to distinguish colour.

Question 18

Rod cells - synaptic connections??

Answer 18

Groups if rods synapses with a single bipolar neurone - they display convergence !!

Question 19

Cone cells - synaptic connections??

Answer 19

A 1:1 connection between cone cells and bipolar neurones!

Question 20

What is a stimulus ?

Answer 20

A detectable change in the external or internal environment of an organism that produces a response In the organism.

Question 21

Why do some optic cells contain black pigment??

Answer 21

This pigment absorbs the light and stops the light from being reflected!!

Question 22

Explain how rod cells have high sensitivity??

Answer 22

More than one rod cell to each bipolar neurone gives an accumulate / higher impulse and reaching the active potential in lower light intensities because they can overcome the threshold value!

Question 23

Which part of the retina has the highest number if receptor cells??

Answer 23

The FOVEA

Question 24

A myelinated axon conducts impulses faster than a non-myelinated axon. Explain the difference??

Answer 24

In myelinated…..
1. The action potential / depolarisation only at nodes of Ranvier.
⭐️⭐️⭐️
2. Nerve impulse jumps from node to node/ saltatory conduction
⭐️⭐️⭐️
3. Action potential / impulse does not travel along whole length

Question 25

Resting potential = ?

Answer 25

Potential difference across the plasma membrane when the cell is at rest

Question 26

Action potential = ?

Answer 26

The brief change in polarity when the neuron is activated (nerve impulse )

Question 27

The cells of the body need to communicate with one another. What is the name given to this process of communication???

Answer 27

Cell signalling 💕💕

Question 28

Sensory neurones??

Answer 28

Transmit nerve impulses from receptors to CNS ✨✨✨

Question 29

Relay neurones ??

Answer 29

Transmit nerve impulses between other neurones ✨✨✨

Question 30

Motor neurones ???

Answer 30

Transmit nerve impulses from CNS to effector ✨✨✨

Question 31

The reflex arc = ?

Answer 31

``` Stimulus ⬇️ Receptor ⬇️ Sensory neuron ⬇️ Relay neuron ⬇️ Motor neuron ⬇️ Effector ⬇️ Response ```

Question 32

The purpose / use of the reflex arc ??

Answer 32

Reflex arc enables a rapid response to a stimulus, without the need to involve the brain. ✨✨✨ V. Useful for protecting the body from damage!!!

Question 33

Nerve impulses always travel from.....?

Answer 33

From Densrites to the Axon!! ✨✨✨

Question 34

Effect of myelin sheath on conduction?

Answer 34

Myelin sheath helps speed up transmission of nerve impulses (conduction)

Question 35

Schwann cells = ?

Answer 35

Schwann cells wrap around axon multiple times..... Multiple layers of cell membranes.... INSULATED nerve cells (prevents the nerve impulses passing through it)

Question 36

Nodes of Ranvier = ?

Answer 36

Gaps between Schwann cells where the axon is exposed 💁

Question 37

Saltatory conduction = ?

Answer 37

Nerve impulses jumping from node to node 🍸👯🎉

Question 38

Threshold to fire ?

Answer 38

The minimum amount of stimulus required in order to activate the nerve cell and cause an action potential 🙌💕✨ A.K.A. The all or nothing law

Question 39

Cell signalling = ?

Answer 39

Communication between cells! E.g. Communication between nerve cells across a synapse