The Nervous system and the Endocrine system

Question 1

What is the Nervous system?

Answer 1

• Specialised network of cells based on electrical and chemical signals
• Known as the primal internal communication system
• Consists of two subsystems: central nervous system, peripheral nervous system

Question 2

What are the two main functions of the nervous system?

Answer 2

• Collects, processes and responds to information in the environment
• To co-ordinate the working of different organs and cells in the body

Question 3

What is the Central Nervous system?

Answer 3

• Brain and Spinal cord
• Brain:
• ‘Centre of all awareness’
• Cerebral cortex is 3mm thick and highly developed in humans
• Spinal cord:
• Extension of the brain
• Passes messages to and from the brain
• Connects nerves to the PNS
• Responsible for reflex actions

Question 4

What is the Peripheral Nervous system?

Answer 4

• Transfers messages via neurons to and from CNS
• Further divided into: Autonomic Nervous system - governs vital functions e.g breathing, heart rate, digestion, sexual arousal and stress responses and Somatic Nervous system - governs muscle movement and receives info from sensory receptors

Question 5

How does the Endocrine system work?

Answer 5

• Glands e.g Thyroid produce hormones e.g thyroxine that are secreted into bloodstream and effects cells with a receptor for said hormone.
• most hormones affect multiple organs e.g thyroxine increases heartrate and affects metabolic rate
• Pituitary gland = master gland (controls release of hormones from all other endocrine glands in the body)

Question 6

How are Endocrine system and Autonomic Nervous system linked?

Answer 6

• e.g during a stressful event: when a stressor is perceived the hypothalamus activates pituitary gland which triggers activity in the sympathetic branch of the AMS
• ANS changes from parasympathetic state to physiologically aroused sympathetic state

Question 7

How does Fight of flight occur/ what are the features?

Answer 7

Adrenaline: released from the adrenal medulla into bloodstream. Adrenaline triggers physiological changes which creates physiological arousal necessary for flight/fight

Immediate and Automatic: as soon as the threat is detected, an acute response and an automatic reaction

Parasympathetic action: once threat has passed parasympathetic branch of the ANS works in opposition to the sympathetic nervous system. Acts as a break to fight/flight activities - rest and digest response

Question 8

What does the Sympathetic state do?

Answer 8

• Increases heart rate, breathing rate, dilates pupils, inhibits digestion, inhibits saliva production, contracts rectum

Question 9

What does the Parasympathetic state do?

Answer 9

• decreases heart rate, breathing rate, constricts pupils, stimulates digestion, stimulates saliva production, relaxes rectum