Biological structures

Question 1

What is the nervous system?

Answer 1

A specialised network of cells that is our main communciation system. It is based on chemical and electrical signals.

Question 2

What is the function of the nervous sytem?

Answer 2

• Allows the body to respond to chnages in the internal or external environment (stimuli)
• Allows the body to coordinate its actions by communicating with a central “control point” (the brain)

Question 3

What is the central nervous system?

Answer 3

Brain: centre of consious awareness

• The cerebral cortex

Spinal cord: Extension of the brain (connects via the brain stem)
Responsible for refelex actions such as pulling hand off a plate

Question 4

What is the peripheral nervous system?

Answer 4

Consists of paired (either side of the body) cranial and spinal nerves

• It sends information about the external and internal environment via sensory neurones to the CNS from receptors
• It then transmits messages from the CNS to muscles or glands

It has two different systems: somatic nervous system and autonomic nervous system

Question 5

What is the somatic nervous system?

Answer 5

• Transmits information from receptor cells to the CNS
• Recieves information from the CNS that directs muscles to act
• Responsible for voluntary movement and connects the CNS to do the same

Question 6

What is the autonomic nervous system?

Answer 6

Transmits information to and from internal body organs for autonomic bodily functions. It has two main divisions:

• The sympathetic nervous system gets the body ready for action. It is the “flight or fight” system
• The parasympathetic nervous sytem calms the body down. It is the “rest and digest” system

Question 7

What is the sympathetic nervous system?

Answer 7

Arousal

• Activates the internal organs by triggering release of adrenaline
• It increases the supply of glucose to ready muscles for increased activity (e.g it increases heart rate and breathing rate)

Question 8

What is the parasympathetic system?

Answer 8

Calm

• Activates when the body is trying to conserve/store resources
• It has the opposite side effects of the sympathetic nervous system, decreasing the supply of glucose ad oxygen to the muscles and increases the rate of digestion

Question 9

What is the endocrine system?

Answer 9

A specialised system of tissues, mainly glands, that works alognside the nervous system. It is based on only chemical signals from hormones

Question 10

What is the function of endocrine system?

Answer 10

Regulates vital functions of the body by releasing hormones, mostly via blood, to communicate messages to target organs.
It operates slower than the nervous system, but the effects are longer lasting

Question 11

What does the hypothalamus do?

Answer 11

Produces hormones that control the pituritary gland

Question 12

What does the pituritary gland?

Answer 12

Known as the “master gland” because it releases hormones to control other glands in the endocrine system (e.g ACTH to stimulate adrenal glands)

Gland –> hormone –> effect

Question 13

What does the thyroid gland do?

Answer 13

Produces hormones such as thyroxine. The thyroid is responsible for controlling metabolism and growth

Question 14

What is the parathyroid glands?

Answer 14

Produce a hormone called parathyroid
This helps control the levels of minerals such as calcium within the body

Question 15

What does the adrenal gland do?

Answer 15

Produces hormones such as adrenaline
Responsible for the “flight or fight” response

Question 16

What does the pancreas do?

Answer 16

Endocrine glands in the pancreas produce insulin and glucagen, which regulate the level of glucose in the blood

Question 17

What do the gonads (ovaries and testes) do?

Answer 17

Produce sex hormones, e.g testosterone snd oestrogen.
These are important in reproduction and the development of sex organs and secondary sex characteristics

Question 18

What is flight or fight?

Answer 18

Refers to the way an animal responds when stressed. The body becomes physiologically aroused in readiness to fight or flee from threat
Response is a result of the nervous sytem and the endocrine working together

Question 19

What is the process of flight or fight?

Answer 19

1. When an individual is faced with a threat, an area of the brain called the amygdala is mobilised
2. It sends a distress signal to the hypothalamus, which then triggers the pituritary gland to activate the sympathetic branch of the ANS
3. This sympathetic activation causes the adrenal medulla (middle of the adrenal gland) to release adrenaline, leading to a range of physiological effects

Question 20

What are three physiological effects of sympathetic state?

Answer 20

Increases heart rate
Dilates pupils
Inhibits digestion

Question 21

What are three physiological effects of parasympathetic state?

Answer 21

Decreases heart rate
Constricts ppupils
Stimulates digestion