The Nervous System and Endocrine System

Question 1

Nervous system:

Answer 1

Consists of the central nervous system and the peripheral nervous system.

Question 2

CNS:

Answer 2

Consists of the brain and spinal cord and is the origin of all complex commands and decisions.

Question 3

Peripheral nervous system:

Answer 3

Send information to the CNS from the outside world and transmits messages from the CNS to muscles and glands in the body.

Question 4

Somatic Nervous System: (PNS)

Answer 4

Transmits information from the receptor cells in the sense organs to the CNS. It also receives information from the CNS that directs muscles to act.

Question 5

Autonomic nervous system: (PNS)

Answer 5

Transmits information to and from internal bodily organs. It is automatic as the system operates involuntarily. It has two main divisions the sympathetic and parasympathetic nervous systems. Controls heart rate and breathing rates.

Question 6

How do the two parts of the autonomic system work together?

Answer 6

The autonomic nervous system is also subdivided into the sympathetic and parasympathetic branches. These branches work as part of an antagonistic pair during the ‘rest and digest’ response, and are crucial in producing the physiological arousal needed to maintain the fight or flight response.

Question 7

What do para/sympathetic nervous systems do?

Answer 7

For example, the sympathetic nervous system increases heart rates, breathing rate, causes vasoconstriction (narrowing of blood vessels) and pupil dilation, whilst the parasympathetic nervous system decreases heart rate, breathing rates, causes vasodilation and pupil constriction.

Question 8

What is the endocrine system and how are hormones transported in the blood?

Answer 8

The endocrine system is the main chemical messenger system of the body, where hormones are secreted into the bloodstream from glands, and then are transported towards target cells in the blood, with complementary receptors.

Question 9

What is the pituitary gland and what does it do?

Answer 9

The pituitary gland is considered to be the ‘master’ gland because it controls the release of hormones from all other glands in the body.

Question 10

Where is thyroxine secreted from and what does it do?

Answer 10

For example, the thyroid releases the hormone thyroxine, which increases heart rate.

Question 11

Where is adrenaline secreted from and what does it do?

Answer 11

The adrenal gland releases adrenaline which creates the physiological arousal preceding the fight or flight response, through increasing the activity within the sympathetic branch of the nervous system.

Question 12

1st stage of flight or fight response:

Answer 12

1.The body senses and becomes aware of a stressor in the
environment e.g. the sound of a speeding car.

Question 13

2nd stage of flight or fight response:

Answer 13

Through sensory receptors and sensory neurones in the PNS, this information is sent to the hypothalamus in the brain which coordinates a response and triggers increased levels of activity in the sympathetic branch of the ANS.

Question 14

3rd stage of flight or fight response:

Answer 14

Adrenaline is released from the adrenal medulla in the adrenal glands, and is transported to target effectors, via the
blood and through the action of the endocrine system.

Question 15

4th stage of flight or fight response:

Answer 15

This results in the saliva production being inhibited and a greater breathing rate. This creates the physiological response needed to sustain the fight or flight response, whose adaptive purpose is to enable us to escape the stressor and so increase the likelihood of our survival.

Question 16

5th stage of flight or fight response:

Answer 16

Once the stressor is no longer a threat, as part of an antagonistic pairing, the hypothalamus triggers less activity in the sympathetic branch and more activity in the parasympathetic branch of the ANS. This is also referred to as the rest and digest response, due to the parasympathetic
branch decreasing the activity which was originally increased through the action of the sympathetic branch.