A

Question 1

What is neurulation?

Answer 1

The development of the nervous system

Question 2

How does the neural tube develop?

Answer 2

1. Ectoderm of dorsal side is the neural plate
2. Cells on the neural plate changes shape, plate folds onwards and forms a groove
3. Separates from rest of ectoderm
4. Neural tube extends and becomes spinal cord

Question 3

How are neurons developed?

Answer 3

1. Differentiation of neural tube in embryonic development
2. Nervous system is formed
3. Immature neurons migrate to final location

Question 4

How do axons develop?

Answer 4

An axon grows from each immature neuron in response to chemical stimuli. Some extend beyond the neural tube to the body.

Question 5

How do short axons work?

Answer 5

Form connections between Central nervous system

Question 6

How do long axons grow?

Answer 6

Connect to any part of the body

Question 7

How do synapses develop?

Answer 7

• developing neuron forms synapses
• synapses grow in between axons
• new synapses are formed throughout life with experience
• transmission across a synapse strengthens synapse

Question 8

What is neural plasticity?

Answer 8

Synapses develop and are eliminated with experience in life. Highest plasticity up to age of 6. If not used, are eliminated (neural pruning) if used, transmission across a synapse strengthens the synapse.

Question 9

What is spina bifida?

Answer 9

Incomplete closure of the neural tube

Question 10

How does one accumulate spina bifida?

Answer 10

After neurulation, the centrum encloses and protects the spinal cord, as tissues from the centrum migrate around the neural meeting as an arch. In spina bifida, the arch is not properly fused

Question 11

Where is spina bifida most common?

Answer 11

In the lower back

Question 12

What do strokes cause?

Answer 12

Reorganisation of brain function in recovery to supplement damage

Question 13

What happens in an ischemic stroke?

Answer 13

There is a disruption of blood to the brain, causing the brain to be deprived of oxygen and glucose, so cell respiration ceases in neurons and they irreparably are damaged and die

Question 14

How is the brain developed?

Answer 14

The anterior part of the neural tube forms the brain in cephalization

Question 15

What is the function of the medulla oblongata?

Answer 15

Autonomic control of the heart, gut muscles, breathing, blood vessels

Question 16

What is the function of the cerebellum?

Answer 16

Coordination- eg unconscious functions like balance, posture

Question 17

What is the function of the hypothalamus?

Answer 17

It is an interface between the brain and pituitary gland and synthesises hormones

Question 18

What is the function of the pituitary gland?

Answer 18

Secreted hormones of the hypothalamus in posterior lobe and in anterior love produces hormones for body functions

Question 19

What is the function of the cerebral hemispheres?

Answer 19

Interesting centre for complex functions, eg learning, memory, speech, emotion, reasoning, ordering, self awareness

Question 20

What are different methods of brain research?

Answer 20

• lesion studies
• autopsy
• animal research
• MRI and fMRI to analyse pattern recognition and judgement of speed and movement

Question 21

What is broca’s area?

Answer 21

A part of the left cerebral hemisphere associated with speech

Question 22

What is the nucleus accumbens?

Answer 22

Pleasure and reward centre in each cerebral hemisphere which releases dopamine

Question 23

What is the autonomic nervous system?

Answer 23

Centre of involuntary responses processed by the medulla oblongata. Comprises sympathetic and parasympathetic nervous system.

Question 24

What do the parasympathetic and sympathetic nervous systems do?

Answer 24

They have contrary effects- parasympathetic increases actions, and processes body functions, sympathetic decreases body functions and is associated with survival processes

Question 25

How does the pupil reflex show brain damage?

Answer 25

If light is shine in eye, pupil should constrict. The medulla controls this involuntary reaction so if it does not trigger the parasympathetic nervous system to cause circular muscle fibres to constrict, there is damage to the medulla.

Question 26

What is the structure of the cerebral cortex?

Answer 26

- outer layer of cerebral hemispheres - 2-4mm thick - 6 layers of neurons - enlarged with evolution- folding to fit in cranium - left cerebral hemisphere receives input from sensory receptors on right side and vice versa

Question 27

Why does the brain require a large amount of energy from respiration?

Answer 27

To maintain and re-establish resting potential and synthesise neurotransmitters

Question 28

What are the different specialised receptors?

Answer 28

- mechanoreceptors - chemoreceptors - thermoreceptors - photoreceptors

Question 29

How do olfactory receptors work?

Answer 29

They are located in the epithelium of the upper nose, and odorant receptors are in the membrane. Volatile chemicals are smelled in nose and odorants from food in mouth can pass to nasal epithelium.

Question 30

What do the cornea and lens do?

Answer 30

They focus light on to the retina

Question 31

What do rods and cones do?

Answer 31

They are stimulated by light and detect the image focused on the retina and convert it to neural signals

Question 32

How do Rods work?

Answer 32

They are sensitive and work well in dim light. Bright light causes the pigment to be temporarily bleached. They cannot respond selectively to colours.

Question 33

How do cones work?

Answer 33

There are 3 types which absorb different wavelengths: red, green and blue.

Question 34

How do bipolar cells work?

Answer 34

They lead impulses from rods and cones to ganglion cells, acting as a synapse. If rods and cones are not stimulated, they depolarise and release an inhibitory neurotransmitter to bipolar cell which becomes hyperpolarised and don’t transmit to ganglion. When light is absorbed by rods and cones, rods and cones hyperpolarise and stops sending inhibitors to bipolar cells, which depolarise, activating adjacent ganglion.

Question 35

What do ganglion cells do?

Answer 35

Send an action potential along the auditory nerves to the brain

Question 36

What is the middle ear?

Answer 36

An air filled chamber between the outer and inner ear.

Question 37

What is the eardrum?

Answer 37

A flexible, thin, taut sheet that separates middle ear from outer

Question 38

What do the oval and round windows do?

Answer 38

Separate the middle ear from inner ear

Question 39

Which bones form a connection between the eardrum and oval window?

Answer 39

Hammer, anvil wne stirruo

Question 40

What do the ossicles do?

Answer 40

Transmit vibrations from the eardrum to the oval window, amplifying the sound 20 fold as the oval has a small SA

Question 41

What do sensory hairs of the cochlea doing?

Answer 41

They detect sounds. Vibrations of the oval window push cochlea fluid forwards, transmitting vibrations to cochlea. Activation of different hairs distinguishes pitch and vibrations depolarise hair cells, which release neurotransmitters triggering an action potential along the auditory nerve.