A Flashcards Preview

Biology COPY > A > Flashcards

Flashcards in A Deck (41)
Loading flashcards...

What is neurulation?

The development of the nervous system


How does the neural tube develop?

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


How are neurons developed?

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


How do axons develop?

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


How do short axons work?

Form connections between Central nervous system


How do long axons grow?

Connect to any part of the body


How do synapses develop?

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


What is neural plasticity?

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.


What is spina bifida?

Incomplete closure of the neural tube


How does one accumulate spina bifida?

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


Where is spina bifida most common?

In the lower back


What do strokes cause?

Reorganisation of brain function in recovery to supplement damage


What happens in an ischemic stroke?

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


How is the brain developed?

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


What is the function of the medulla oblongata?

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


What is the function of the cerebellum?

Coordination- eg unconscious functions like balance, posture


What is the function of the hypothalamus?

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


What is the function of the pituitary gland?

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


What is the function of the cerebral hemispheres?

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


What are different methods of brain research?

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


What is broca’s area?

A part of the left cerebral hemisphere associated with speech


What is the nucleus accumbens?

Pleasure and reward centre in each cerebral hemisphere which releases dopamine


What is the autonomic nervous system?

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


What do the parasympathetic and sympathetic nervous systems do?

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


How does the pupil reflex show brain damage?

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.


What is the structure of the cerebral cortex?

- 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


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

To maintain and re-establish resting potential and synthesise neurotransmitters


What are the different specialised receptors?

- mechanoreceptors
- thermoreceptors


How do olfactory receptors work?

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.


What do the cornea and lens do?

They focus light on to the retina