Biopsychology

Question 1

What are dendrites?

Answer 1

They extend from the cell and carry electrical impulses from other neutrons towards the cell body.

Question 2

What are axon?

Answer 2

They carry electrical impulses away from the cell body.

Question 3

What is the myelin sheath?

Answer 3

The axon is covered in this fatty substance. It’s main purpose is to increase speed of impulses.

Question 4

What is the role and structure of sensory neurons?

Answer 4

They carry impulses from sensory receptors to the CNS. They have long dendrites and short axon.

Question 5

What is the role and structure of relay neurons?

Answer 5

They help sensory and motor neurons communicate. They carry info across the CNS from sensory neurons to motor neurons. They have short dendrites and short axon.

Question 6

What is the role and structure of motor neurons?

Answer 6

They are responsible for either directly or indirectly controlling muscles. They carry impulses from CNS to an effector. They have short dendrites and long axon.

Question 7

What does the peripheral nervous system do?

Answer 7

Brings info from the senses to the CNS and transmits info from CNS to muscles and glands. It consists of all other nerves which are not part of the CNS.

Question 8

What two systems is the peripheral nervous system divided into?

Answer 8

Somatic nervous system and autonomic nervous system.

Question 9

What does the somatic nervous system do?

Answer 9

Connects external sensory organs through the CNS to the muscles. Transmits info to and from senses and to and from CNS.

Question 10

What does the autonomic nervous system do? And what is its sub-systems?

Answer 10

It is responsible for vital functions (e.g. heart rate). It transmits info from and to the internal body organs and operates automatically.

1) Sympathetic nervous system - stimulates functions like digestion and is involved in fight our flight response (stimulates secretion of adrenaline).
2) parasympathetic nervous system - slows functions like digestion and is also involved in fight or flight.

Both sub- systems interact to maintain homeostasis.

Question 11

Describe the SAM pathways role in fight or flight.

Answer 11

The amygdala sends a distress signal to the hypothalamus. The hypothalamus is in charge of stress response and connects info from nervous system to the endocrine system using the pituitary gland. When a stress is triggered hypothalamus signals to other structures the pituitary gland and the sympathetic ganglia. Finally, the adrenal medulla releases adrenaline which causes the fight or flight response.

Question 12

Describe the PAS pathway role in the fight or flight response.

Answer 12

The hypothalamus releases CRF which activates the pituitary gland which releases ACTH, which activates the adrenal cortex. This then releases corticosteroids e.g. cortisol.

Question 13

What does the adrenal medulla and sympathetic ganglia do?

Answer 13

The sympathetic anglia are connected to the internal organs. When activated they affect the functioning of the organs. They are also connected to the adrenal medulla. The adrenal medulla releases adrenaline. This hormone stimulates the sympathetic ganglia keeping their activity at a high level.

Question 14

What does the adrenal cortex do?

Answer 14

It releases chemicals called corticosteroids (e.g. cortisol).

Question 15

What are the Nodes of Ranvier?

Answer 15

Breaks in the myelin sheath.

Question 16

What does the somatosensory cortex do?

Answer 16

The 5 senses. Incoming info from sensory neurones towards CNS.

Question 17

What does the motor cortex do?

Answer 17

Outgoing info towards muscles in the form of motor neurones.

Question 18

What is the CNS?

Answer 18

It consists of the brain and the spinal cord. This is where all complex processing of info is done and decisions are made.

Question 19

Describe the synaptic transmission.

Answer 19

The process by which a nerve impulse passes across the pre-synaptic neurone to a post-synaptic neurone. In other words, synaptic transmission is the process by which one neurone communicates with another.

Question 20

Describe the process of synaptic transmission.

Answer 20

1) Info is passed down the axon of the neurone as electrical impulses (AKA action potential).
2) Once the impulse gets to the end of the neurone it must cross over the synaptic gap (synaptic cleft) between the pre and post synaptic neurone.
3) At the end of the neurone (axon terminal) are synaptic vesicles, which contain neurotransmitters.
4) When the impulse reaches the synaptic vesicles it triggers (by opening up calcium channels) the vesicles to move towards the membrane and release neurotransmitters.
5) The neurotransmitters diffuse across the synaptic cleft and some bind to the receptor sites on the post-synaptic neurone.
6) Neurotransmitters that don’t bind are either absorbed/broken down by enzymes or they get reuptaken back into the pre-synaptic neurone.
7) The neurotransmitters effect the likelihood of the post-synaptic neurone firing.

Question 21

What are neurotransmitters?

Answer 21

Chemical messengers.

Question 22

What does inhibitory neurotransmitters do?

Answer 22

Decreases the likelihood a neurone will fire.

Question 23

What does excitory neurotransmitters do?

Answer 23

Increases the likelihood the neurone will fire.

Question 24

What does summation mean?

Answer 24

The summed total of inhibitory + excitory neurotransmitters.

Question 25

What do neurotransmitters need to have for the post-synaptic neurone to fire?

Answer 25

Chemicals with a great enough charge to carry on the signal to the next synapse (i.e. more excitory ones than inhibitory).

Question 26

How is the endocrine system different from the nervous system?

Answer 26

It acts more slowly, but it’s effects are more widespread and powerful. Is also uses the bloodstream to deliver hormones to its target sites (which is why it is slower).

Question 27

What is the endocrine systems main function?

Answer 27

To maintain homeostasis.

Question 28

What are hormones?

Answer 28

• Chemicals that circulate in the blood and carried to target sites.
• Usually only affect a limited number of cells.
• When enough cells are stimulated, this results in a physiological reaction in the target cells.

Question 29

What must the target cells have in order for a hormone to work?

Answer 29

A particular receptor site.

Question 30

What is crucial for hormone transmission?

Answer 30

The timing of release and quantity of hormones.

Question 31

How do glands and hormones work?

Answer 31

Levels of hormones are controlled by feedback.

Signal is sent from hypothalamus to the pituitary gland in the form of a ‘releasing hormone’. The pituitary gland secretes a ‘stimulating hormone’ and this signal targets glands to secrete their hormone. As levels of hormone increase the hypothalamus stops the secretion of the releasing hormone and the pituitary gland shuts down the secretion of the stimulating hormone.

Question 32

What is the function of the pituitary gland?

Answer 32

Called the “master gland”. Some of the hormones released are important for regulating the endocrine system. The anterior pituitary gland secretes LH and FSH, which stimulates overlies to produce oestrogen and progesterone or testosterone and sperm. The posterior pituitary releases oxytocin which stimulates the uterus to contract during labour and plays a role in bonding.

Question 33

What is the function of the adrenal gland?

Answer 33

It is an important part of the fight or flight response as it facilitates the release of adrenaline.

Question 34

Describe the function of the thyroid gland.

Answer 34

It regulates the body’s metabolic rate and protein synthesis. It produces thyroxin, which increases heart rate and metabolic rates.