The Nervous And Endocrine System Flashcards
What is the nervous system?
A specialised network of cells in the human body.
Our primary internal communication system.
What are the two main functions of the nervous system?
- to collect, process and respond to information in the environment
- to co-ordinate the working of different organs and cells in the body.
What is the nervous system divided into?
The central nervous system and the peripheral nervous system.
Why is the central nervous system made up of?
The brain and the spinal cord.
Cerebral cortex
The brains outer layer.
Highly developed in humans.
Distinguishes our higher mental functions from those of animals.
Spinal cord
An extension of the brain.
Responsible for reflex actions.
What does he peripheral nervous system do?
Transmits messages via millions of neurons to and from the CNS.
What is the PNS sub-divided into?
Autonomic nervous system - governs vital functions in the body.
Somatic nervous system - controls muscle movement and receives information from sensory receptors.
Endocrine system
Works alongside the NS to control vital functions in the body.
Acts more slowly but has widespread and powerful effects.
Gland
An organ in the body that synthesises substances such as hormones
Hormones
Chemical substances that circulate the bloodstream and only affect target organs.
Produced in large quantities but disappear quickly.
What is the major endocrine gland?
Pituitary gland
Located in the brain.
Often called the ‘master gland’ as it controls the release of hormones from all other endocrine glands in the body.
Fight or flight response
The way animals respond when stressed.
The body becomes physiologically aroused in readiness to fight and aggressor or, in some cases flee.
Fight or flight - explanation
Stressor perceived.
Hypothalamus triggers activity in sympathetic branch of the ANS.
ANS changes from parasympathetic to sympathetic state.
Adrenaline released from the adrenal medulla, creating physiological arousal needed.
Once threat has passed, body returns to parasympathetic state.
Biological changes associated with the sympathetic state
Increased heart rate, increased breathing rate, dilates pupils, inhibits digestion, inhibits saliva production and contracts rectum.
