The Nervous System & The Endocrine Sytem

Question 1

What are the nervous systems 2 main functions

Answer 1

1. To collect, process and respond to the info in the environment
2. To co-ordinate the working of different organs and cells in the body

Question 2

What is the nervous system

Answer 2

• specialised network of cells in the human body
• is our primary internal communication system
• based on electrical and chemical signals

Question 3

The nervous system is split into 2 subdivisions - CNS

Answer 3

Made up of the Brian and spinal cord

• brain is the centre of consciousness and awareness
• outer layer = cerebral cortex covers the brain
• brain is highly developed
• divided into 3 hemispheres
  Spinal cord is an extension of the brain - passes messages to and from brain + connects nerves to the PNS. Responsible for reflex actions

Question 4

PNS

Answer 4

Transmits messages by neurones, to and from the central nervous system.
Divided into:
1. Autonomic NS - vital functions e.g. breathing
2. Somatic NS - muscle movement and receives info from sensory receptors

Question 5

Endocrine system - Glands and hormones

Answer 5

• glands produce hormones
• hormones are secreted into the blood stream and affect any cell in the body that has a receptor for that specific hormone
• thyroid gland produces thyroxine - effects cells in the heart and cells throughout body increasing metabolic rate and growth rates
• pituatry gland - located in the brain - controls the release of hormones from all other endocrine glands

Question 6

Endocrine and ANS - fight or flight

Answer 6

• stressful event
• stressor is received, hypothalamus activates pituatry gland
• triggers activity in the sympathetic branch of ANS
• ANS changes from parasympathetic -> sympathetic

Question 7

Role of adrenaline in fight or flight

Answer 7

• stress hormone is released from the adrenal medulla into the bloodstream
• adrenline triggers physiological changes in the body, increasing arousal needed for flight.

Question 8

Immediate and automatic

Answer 8

• all the physiological changes happen as soon as the threat is detected
• acute responce and an automatic reaction in the body

Sympathetic: increases HR, BR, dialate pupils, inhibits digestion, saliva production, contracts rectum

Parasympathetic: opposite

Question 9

Parasympathetic action

Answer 9

• once threat has passed, the PNS returns to resting state
• PNS branch of ANS works in opposition to the SNS

Question 10

Process of the stress responce

Answer 10

1. Amygdala sends stress signal to the hypothalamus
2. Hypothalamus releases CRH into blood stream
3. Pituatry gland releases ACTH inot blood stream
4. SNS prepares the body for action - PNS dampens the stress response once the threat has passed
5. Adrenal medulla releases adrenaline into blood stream, causes physiological changes e.g. increased blood sugar, HR, BR