DIVISIONS OF THE NERVOUS SYSTEM

Question 1

Key features of Nervous System

Answer 1

> Specialised network of cells and primary communication system.
Based on electrical (and chemical) signals
Nervous system has two main functions; 1. To collect, process and respond to information in environment. 2. Co-ordinate working of different organs and cells in the body.

Question 2

Key features of Endocrine System

Answer 2

> Based on hormones
Works alongside the nervous system to control vital functions in body
Works more slowly than nervous system (seconds not milliseconds) but has widespread and powerful effects.

Question 3

Glands

Answer 3

> Organs in the body that produce hormones.
Key endocrine gland, pituitary gland, located in brain, called the master gland because it controls the release of hormones from all other endocrine glands in the body

Question 4

Hormones

Answer 4

> Secreted in bloodstream and affect any cell in body that has a receptor for that particular hormone.
ie. thyroxine is produced by thyroid gland, affects cells in heart and also cells throughout the body which increase metabolic rates, and in turn growth rates.

Question 5

Sympathetic State

Answer 5

>Increases heart rate
>Increases breathing rate
>Dilates pupils
>Inhibits digestion
>Inhibits saliva production
>Contracts rectum

Question 6

Parasympathetic State

Answer 6

>Decreases heart rate
>Decreases breathing rate
>Constricts pupils
>Stimulates digestion
>Stimulates saliva production
>Relaxes rectum

Question 7

How do the endocrine system and ANS work together during fight or flight?

Answer 7

> Stressor perceived by hypothalamus which activates the pituitary
Sympathetic nervous system is aroused
Adrenaline (stress hormone) is released from the adrenal medulla into bloodstream. This delivers the aroused state causing changes in target organs in the body eg. increased heart rate, dilation of pupils. This is fight or flight
Immediate and automatic, happens as soon as threat is perceived
Parasympathetic nervous system takes over once the threat has passed. This returns the body to its resting state, acts as a ‘brake’ and reduces activities of the body.

Question 8

Structure of the Central Nervous System (CNS)

Answer 8

> CNS is made up of the brain and spinal cord

Question 9

The brain (CNS)

Answer 9

> Brain is the centre of conscious awareness
Outer layer is cerebal cortex, 3mm thick, highly developed in humans and is what distinguishes our higher mental state than animals
Divided into two hemispheres

Question 10

The Spinal Cord (CNS)

Answer 10

> An extension of the brain and responsible for reflex actions
Passes messages to and from the brain and connects nerves to the PNS

Question 11

Structure and Function of the Peripheral Nervous System (PNS)

Answer 11

> Transmits messages, via millions of neurons, to and from the nervous system.
Subdivided into Autonomic Nervous System (ANS) and Somatic Nervous System (SNS)

Question 12

Autonomic Nervous System

Answer 12

Governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses

Question 13

Somatic Nervous System

Answer 13

Governs muscle movement and receives information from sensory receptors

Question 14

Divisions of Human Nervous System

Answer 14

1. Human Nervous System
2. Peripheral Nervous System and Central Nervous System
3. PNS, Autonomic Nervous System and Somatic Nervous System 3. CNS, Brain and Spinal Cord
4. ANS, Sympathetic Nervous System and Parasympathetic Nervous System