Topic 11 Nervous System

Question 1

he nervous system enables humans to react to their ——–
and coordinate their ————-

Answer 1

surroundings
behaviour

Question 2

Explain how the structure of the nervous system structure as well ot is adapted to its functions summarised :

Answer 2

Adaptations
reflex arc doesn’t travel to brain so quicker

Information from receptors passes along cells (neurones) as electrical impulses to the central nervous system (CNS).
The CNS is the brain and spinal cord.
The CNS coordinates the response of effectors which may be muscles contracting or glands secreting hormones.
Stimulus - Receptor - Coordinator - Effector - Response

Question 3

Explain how structures in a reflex arc relate to their function:

Answer 3

1. When you touch an object a receptor in your skin is stimulated. An electrical impulse from a receptor passes along a sensory neurons to the CNS- in this case the spinal cord
2. When an impulse from the sensory neurone arrives at synapse with a relay neurone, a chemical is released. The chemical diffuses across the synapse to the relay neurone where it sets off a new electrical impulse that travels along the relay neurone
3. When the impulse reaches the synapse between the relay neurone and a motor neurone returning to the arm, another chemical is released. Again, the chemical diffuses across the synapse and starts a new electrical impulse travelling down the motor neurone to the effector
4. When the impulse reaches the effector organm it is stimulated to respond.

Question 4

why reflex actions are important quick bullets:

Answer 4

Automatic ( they do not involve the conscious part of the brain)
Rapid; protect from harm

Question 5

Method for carrying out an investigation into the effect of a factor on human reaction time.

Answer 5

Each person has three practice goes before the 5 readings are taken.
Person one places their dominant arm (e.g. right arm) on the table with their hand over the edge
Person one opens their thumb and forefinger so they are 3cm apart
Person two holds a metre ruler so 0 cm is level with the top of their thumb
Person two drops the ruler and person one catches it
Record the distance the ruler fell at the top of the thumb
Repeat 5 times and calculate a mean distance
Convert to reaction time using the conversion table below
Person 1 and 2 now swap round and repeat the experiment.

Question 6

Independent variable

Dependent variable

Answer 6

Person

Distance the ruler fell

Question 7

Control variables

Answer 7

Distance between thumb and finger
Which hand they are catching the ruler with (dominant or non-dominant)
How much they had practised before the experiment
What the person had eaten or drunk before the experiment (e.g. caffeinated drink)
Noise levels in the room
How tired the person is

Question 8

What is someone’s dominant arm/hand?

How else could you measure reaction time?

Answer 8

The hand/arm they use for most tasks

Use a reaction time test online.

Question 9

Describe the main sources of error

Answer 9

The ruler may not held so 0 is at the top of the thumb
Ruler might not be read accurately to the top of the thumb

Question 10

Describe how to improve the accuracy of the experiment

Answer 10

Repeat more times and calculate a mean

Question 11

Suggest an uncontrolled variable

Answer 11

How tired the person was / what the person ate or drank before the experiment

Question 12

Describe how to improve the validity of the experiment

Answer 12

Repeat on a number of different days
Give the people taking part the same food / drink before the experiment

Question 13

Describe how you could change the experiment to investigate something different

Answer 13

Keep the person/people the same but change whether they use the dominant or non-dominant hand
Keep the person/people the same but change how much they practise before the experiment starts.
Keep the person/people the same but change the noise level (e.g. by using headphones and music)
Keep the person/people the same but change what they have eat / drink
Keep the person/people the same but change how tired they are (by doing in the morning / at the end of the day)

Question 14

Consider your answer to the question above

Describe how you could change the experiment to investigate something different

and describe how you would you ensure a valid investigation that would give a valid conclusion that wasn’t just about one person

Answer 14

Carry out the experiment on a large group of people / have a large sample size

Question 15

Explain the brain in the context of the nervous system

Answer 15

the brain controls complex behaviour. It is made of billions of interconnected neurones and has different regions that carry out different functions

Question 16

Name the 1st, 3rd and 4th label ignore the 2nd

Answer 16

1st- cerebral cortex
3rd- cerebellum
4th- Medulla

Question 17

cerebral cortex function

Answer 17

consciousness, intelligence, memory & language

Question 18

cerebellum function

Answer 18

coordination of muscular activity

Question 19

medulla function

Answer 19

unconscious activities such as heartbeat & breathing

Question 20

Explain some of the difficulties of investigating brain function and treating brain damage and disease.

Answer 20

the brain is incredibly complex and delicate- the investigation of brain function and any treatment of brain damage or disease is difficult. It also carries risks, such as physical damage to the brain or increased problems with brain function (e.g difficulty with speech).

Question 21

Describe how neuroscientists have been able to map the regions of the brain to particular functions by:
studying patients with brain damage
electrically stimulating different parts of the brain
using MRI scanning techniques

Answer 21

studying patients with brain damage- If a small part of the brain has been damaged the effect this has on the patient can tell you a lot about what damaged part of the brain does. E.g if an area at the back of the brain was damaged by a stroke and the patient went blind, you know that that area has something to do with vision

Electrically stimulating the brain- The brain can be stimulated electrically by pushing a tiny electrode into the tissue and giving it a small zap of electricity y observing what stimulating different parts of the brain does, it’s possible to get an idea of what those parts do. E.g when a certain part of the brain known as the motor area is stimulated it causes muscle contraction and movement.

MRI Scans- A magnetic resonance imaging (MRI) produces a very detailed picture of the brain’s structures. Scientists use it to find out what areas of the brain are active when people are doing things like listening to music or trying to recall a memory.

Question 22

Evaluate the benefits and risks of procedures carried out on the brain and nervous system.

Answer 22

Benefits:

Treatment of Conditions: Procedures such as deep brain stimulation or neurosurgery can treat various neurological disorders, including Parkinson’s disease, epilepsy, and severe depression, improving patients’ quality of life.

Diagnostic Insights: Techniques like MRI and CT scans provide detailed images of the brain, allowing for accurate diagnosis of conditions such as tumors, strokes, or multiple sclerosis.

Research Advancements: Brain surgeries and studies contribute to our understanding of brain functions and neurological diseases, leading to the development of new treatments and therapies.

Risks:

Surgical Risks: Any brain surgery carries risks such as infection, bleeding, or damage to surrounding brain tissue, which can lead to complications like seizures or cognitive impairments.

Anesthesia Risks: Procedures often require anesthesia, which can have side effects and poses risks, especially in patients with pre-existing health conditions.

Psychological Effects: Procedures affecting the brain can lead to changes in personality, mood, or cognitive function, impacting the patient’s mental health and social interactions

Question 23

Retina relating structure to function

Answer 23

contains receptor cells that are sensitive to light intensity and colour

Question 24

Optic nerve:
relating structure to function

Answer 24

carries impulses from the retina to the brain

Question 25

Sclera:
relating structure to function

Answer 25

tough outer layer that has a transparent region at the front called the cornea

Question 26

Iris:
relating structure to function

Answer 26

muscular - controls the size of the pupil and the amount of light reaching the retina

Question 27

Ciliary muscles and suspensory ligaments:
relating structure to function

Answer 27

can change the shape of the lens to focus light onto the retina

Question 28

Describe the process of accommodation.

Answer 28

Changing the shape of the lens to focus on near or distant objects

Question 29

When the eye encounters a near object what happens:

Answer 29

1. The ciliary muscles contract
   2. The suspensory ligaments loosen
   3. The lens becomes thicker and refracts light rays more strongly

Question 30

When the eye encounters a distant object what happens:

Answer 30

1. The ciliary muscles relax
   2. The suspensory ligaments are pulled tight
   3. The lens is pulled thin and only slightly refracts light rays

Question 31

New eye technologies:

Answer 31

now include hard and soft contact lenses, laser surgery to change the shape of the cornea, and a replacement lens in the eye

Question 32

relay neurone which is found in the

Answer 32

central nervous system.

Question 33

Look at the diagram. What part of the eye is identified by label 1?

Answer 33

sclera

Question 34

Explain simple and relfex arc pathways + how they differ

Answer 34

Simple Reflex Arc
A direct pathway involving few neurons (sensory neuron and motor neuron, sometimes one interneuron).
Complex Reflex Arc
An intricate pathway involving multiple interneurons, allowing for more elaborate responses.
Key Differences
Number of Neurons: Simple reflex arcs have fewer neurons; complex reflex arcs have multiple.
Processing Level: Simple arcs are fast and automatic; complex arcs involve more processing and coordination.

Question 35

What type of lens can be used to correct short sight?

Answer 35

concave

Question 36

What type of lens can be used to correct long sight?

Answer 36

convex

Question 37

vitreous body fills

Answer 37

the space in the eye

Question 38

In myopia light rays converge

Answer 38

in front of the retina

Question 39

In hyperopia light rays converge

Answer 39

behind the retina

Question 40

What is the name given to the reflex that changes the shape of the lens in the eye

Answer 40

accommodation reflex

Question 41

. When focusing on distant objects, the shape of the lens in the eye is

Because since the source is far away

Answer 41

long and thin

Since the source is far away, the rays will be nearly parallel so require less bending to focus on the retina.

Question 42

Which part of the eye changes shape to increase or decrease the amount of light that enters into the eye?

Answer 42

iris