The Nervous System And The Endocrine System Flashcards
What is the nervous system?
A specialised network of cells in the human body and is our internal communication system.
What is one difference between the nervous system and the endocrine system?
The nervous system is based in electrical and chemical signals whereas the endocrine system is based on hormones
What are the two main functions of the nervous system?
- To control, process and respond to information in the environment
- To co-ordinate the working of different organs and cells in the body
What two subsystems is the nervous system divided into?
- central nervous system
- peripheral nervous system
Summarise the central nervous system
- made up of brain and spinal cord
- brain is the centre of all conscious awareness
- brain has a 3mm thick outer layer (Cerebral Cortex)
- brain is highly developed in humans
- brain is divided into 2 hemispheres
-spinal cord is extension of brain
- passes messages to and from brain and connects nerves to the PNS
- responsible for reflex actions such as pulling ur hand away from hot plate
Summarise the peripheral nervous system
- transmits messages via millions of neurons (nerve cells) to and from the CNS
- subdivided into the Autonomic Nervous System & Somatic Nervous System
- ANS governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
- SNS governs muscle movement and receives information from sensory receptors
Structure of nervous system
Nervous system divided into PNS and CNS
CNS divided into Brain and Spinal Cord
PNS divided into ANS and SNS
ANS divided into Sympathetic Nervous System and Parasympathetic Nervous System
What is the endocrine system?
One of body’s major information systems that instructs glands to release hormones directly into the bloodstream.
These hormones are carried towards target organs in the body
(Communications via chemicals)
What are glands?
Organ in the body that synthesises substances such as hormones
Give an example of a gland
Thyroid gland - releases thyroxine
Adrenal gland - releases adrenaline
Explain how the endocrine and ANS work together (fight or flight)
- stressor is percieved
- hypothalamus activates pituitary gland
- this triggers activity in the sympathetic branch of the ANS
- ANS changes from parasympathetic state (normal resting) to sympathetic state (physically aroused)
Describe adrenaline in fight or flight
- stress hormone released from adrenal medulla into bloodstream
- triggers physiological changes in the body (increased heart rate) which creates the physiological arousal necessary for fight or flight response
How quickly does fight or flight response happen?
- in an instant as soon as threat is detected (heart beats faster as soon as u encounter a fright)
Explain the parasympathetic action after threat has passed
- once threat has passed, the parasympathetic system returns the body to its resting state
- parasympathetic branch of the ANS works in opposition to the sympathetic nervous system
- parasympathetic system acts as a ‘brake’ and reduces the activities of body that were increases by actions of the sympathetic system.
What are the biological changes associated with sympathetic and parasympathetic response?
Sympathetic state:
- increases heart rate
- increases breathing rate
- dilates pupils
- inhibits digestion
- inhibits saliva production
- contracts rectum
Parasympathetic state:
- decreases heart rate
- decreases breathing rate
- constricts pupils
- stimulates digestion
- stimulates saliva production
Relaxes rectum
EQ: Name and briefly highlight two divisions of the human nervous system. (4)
- The nervous system is divided into CNS and PNS
- CNS consists of brain and spinal cord & is origin of all complex commands and decisions
- PNS transmits messages via millions of neurons to and from the CNS & is further divided into ANS and SNS
EQ: Identify and describe two glands of the endocrine system. (4)
- glands are organs in the body which release hormones into the bloodstream
- the pituitary gland is located in the brain and controls the release of hormones from all the other endocrine glands in the body
- the adrenal gland releases adrenaline into the bloodstream when a threat is detected which leaves humans in a sympathetic state increasing body functions such as heart rate and inhibiting digestion
EQ: Explain what is meant by the fight or flight response. (3)
The fight or flight response is a response which is triggered by a stressor. The body becomes physiologically aroused in readiness to fight an aggressor or, in some cases, flee.
This happens when adrenaline is released into the bloodstream which triggers physiological changes in the body which creates physiological arousal necessary for the fight or flight response
