The Nervous System, Endocrine System, and Localisation of Function

Question 1

What detects stimuli, and what brings about response?

Answer 1

1) Receptors; detect stimuli,
2) Effectors; bring about response to a stimulus.

Question 2

How do receptors communicate with effectors?

Answer 2

• Through the nervous or endocrine system, sometimes both.

Question 3

What are the two key parts of the nervous system?

Answer 3

1) The central nervous system, made up of the brain and the spinal cord,
2) The peripheral nervous system, made up of the neurons that connect the CNS to the rest of the body.

Question 4

What are the two systems of the peripheral nervous system?

Answer 4

1) The automatic nervous system - controls unconscious activities,
2) The somatic nervous system - controls conscious activities.

Question 5

What are the two divisions of the automatic nervous system?

Answer 5

1) The sympathetic nervous system gets the body ready for action,
2) The parasympathetic nervous system calms the body down.

Question 6

What transmits information around the body? what is the structure of this cell?

Answer 6

• Neurons,
• The cell body has dendrites that receive information from other neurons,
• This info passes along the axon in the form of an electrical impulse that ends up at a synaptic knob,
• The myelin sheath insulates the axon to speed up nervous transmission,
• There is a small gap before the next neuron called a synapse,
• Neurotransmitters are chemicals that are released from the synaptic knob, they pass across the synapse, passing on the signal to the dendrites of the next neuron.

Question 7

What are the different types of neuron? what are their functions?

Answer 7

1) Sensory neurons - nerve cells that transmit electrical impulses from receptors to the central nervous system,
2) Relay neurons - transmit electrical impulses between the sensory neurons and motor neurons,
3) Motor neurons - transmit electrical impulses from the CNS to effectors.

Question 8

What is the difference between excitatory neurotransmitters and inhibitory neurotransmitters?

Answer 8

• Excitatory, increase the likelihood that an electrical impulse will be triggered in the postsynaptic neuron,
• Inhibitory, decrease the likelihood that an electrical impulse will be triggered in the postsynaptic neuron.

Question 9

What 5 types of neurotransmitters come up often in psychology? What are there roles?

Answer 9

1) Acetylcholine - an excitatory neurotansmitter involved in voluntary movement, memory, learning, and sleep, too much is linked to depression and too little may result in dementia,
2) Dopamine - helps with movement, attention, and learning, too much linked to schizophrenia, and too little could result in depression and Parkinson’s disease,
3) Noradrenaline - often associated with the fight or flight response, too much is linked to schizophrenia and too little may result in depression,
4) Serotonin - involved in emotion, mood, sleeping, and eating, too little is linked to depression,
5) GABA - an inhibitory neurotransmitter, too much is linked with anxiety disorders.

Question 10

What does the endocrine system involve?

Answer 10

1) Glands - a group of cells that are specialised to secrete a useful substance, such as a hormone,
2) Hormones - chemical messengers, many are proteins or peptides. Some are steroids, e.g. progesterone.

Question 11

How can glands be stimulated? What does this result in?

Answer 11

• Glands can be stimulated by a change in concentration of a specific substance,
• Can also be stimulated by electrical impulses,
• Results in the secretion of hormones.

Question 12

How do hormones get around the body? how do they work?

Answer 12

• Diffuse directly into the blood, then they are taken around the body by the circulatory system,
• Diffuse out of the blood all over the body, but each hormone will only bind to specific receptors, found on the membranes of some cells (called target cells),
• Hormones trigger a response in the target cells.

Question 13

What are the major glands of the endocrine system (9)? and what are their functions?

Answer 13

1) Hypothalamus - produce hormones that control the pituitary gland,
2) Pituitary gland - known as the ‘master gland’; releases hormones to control other glands in the endocrine system,
3) Pineal gland - responsible for the production of melatonin, plays a role in the control of sleep patterns,
4) Thyroid gland - produces hormones such as thyroxine, thyroid is responsible for controlling the body’s metabolic rate, as well as regulating growth and maturation,
5) Parathyroid gland - produces a hormone called the parathyroid hormone; helps control the levels of minerals, e.g. calcium, within the body,
6) Thymus gland - regulates the immune system,
7) Adrenal gland - produces hormones such as adrenaline, responsible for the fight-or-flight response,
8) Pancreas - releases the hormones insulin and glucagon, which regulate blood sugar level,
9) Gonads (ovaries and testes) - produce sex hormones, e.g. testoterone and oestrogen. Important in reproduction and the development of sex organs and secondary sexual characteristics.

Question 14

How does the hypothalamus prepare the body for ‘fight or flight’?

Answer 14

1) In the initial shock response, the hypothalamus triggers activity in the sympathetic branch of the automatic nervous system,
2) stimulates the adrenal medulla within the adrenal glands, releasing adrenaline and noradrenaline into the bloodstream,
3) These hormones affect the body in several ways, including:
- Blood pressure and heart rate increase,
- Digestion decreases,
- Muscles become more tense so that the body is physically responsive,
- Perspiration increases so that the body can cool down,
- Breathing rate increases,
- Pupil size increases,
- Salivation decreases,
4) The result of these changes being that the body is ready to use energy to deal with the stressful situation.

Question 15

What is the motor cortex responsible for?

Answer 15

• Controls voluntary movement.

Question 16

What is the Broca’s area responsible for?

Answer 16

• Production of speech.

Question 17

What is the auditory cortex responsible for?

Answer 17

• Processing information from our ears.

Question 18

What is the Somatosensory cortex responsible for?

Answer 18

• Processing information about touch, pain, temperature, and proprioception (position of the body).

Question 19

What is the visual cortex responsible for?

Answer 19

• Processes information from our eyes.

Question 20

What is the Wernicke’s area responsible for?

Answer 20

• The understanding of language.

Question 21

The brain is split into what? How are these connected? What is the function of them?

Answer 21

• The brain is split into two hemispheres, right and left,
• The two are connected by the corpus callosum,
• Different functions are dominant in each hemisphere,
• Broca’s and Wernicke’s areas are, typically, only found in the left hemisphere; it handles the bulk of language functions. The left hemisphere is generally responsible for logic, analysis, and problem solving,
• The right hemisphere is more concerned with things like spatial comprehension, emotions and face recognition. This is known as hemispheric lateralisation of function.

Question 22

Sperry (1968), method

Answer 22

• Study involved a combination of case studies and experiments,
• The 11 participants had undergone split brain surgery as a result of epilepsy that couldn’t be controlled by medication,
• Control group was used who had no hemisphere disconnection,
• In one of the experiments, participants covered one eye and looked at a fixed point on a projection screen,
• Pictures were projected onto the right/left of the screen at high speeds so that there was no time for eye movement.

Question 23

Sperry (1968), results

Answer 23

• If the picture was shown in the right visual field, all of the participants could say or write what it was without a problem,
• if the image was flashed onto the left the split brain participants couldn’t say or write what they’d seen,
• They could however select a corresponding object with their left hand, which represented what they had been shown to their left eye, even though they didn’t know why they had selected this object.

Question 24

Sperry (1968), conclusion

Answer 24

• Shows that different areas of the brain specialise in different functions, the left hemisphere receives visual information from the right visual field and can convert sight into spoken word and written language,
• Information entering the right hemisphere can, typically, cross over to be processed by the left,
• This cannot happen in split brains; information going to the right hemisphere can’t be converted into language at all, but can still produce a non-verbal response.

Question 25

Sperry (1968), evaluation

Answer 25

• Case studies and experiments; Sperry obtained both qualitative and quantitative data,
• Using both research methods meant that validity and reliability of the study were increased,
• Very small sample size; unable to be fully generalised,
• Epilepsy caused by brain damage, patients had also been on medication that might have affected their brains; hard to conclude that the ways they processed information would be the same as for people without epilepsy or split-brain treatment,
• Criticised in terms of ecological validity; artificial situation, hard to generalise to real-life situations.