The Nervous System Flashcards
1
Q
What is the nervous system?
A
- The human nervous system is a complex network of nerve cells to and from the brain.
- It regulates all body functions.
- It is the source of our consciousness.
2
Q
What are the 2 sections of the nervous system?
A
- Central nervous system.
- Peripheral nervous system.
3
Q
What is the central nervous system?
A
- Made up of the brain and the spinal chord.
- The brain is the centre of awareness. It is divided into 2 hemispheres.
- The spinal cord is an extension of the brain. It transports messages to and from the brain to the peripheral nervous system . It is responsible for reflex actions.
4
Q
What does the central nervous system do?
A
- The CNS controls behaviour and the regulation of the body’s internal processes.
- To do this, the brain must receive information from the sensory receptors (eyes, ears, skin).
- Each brain region is responsible for processing information from different sources.
- Messages must then be sent to the muscles and glands of the body.
5
Q
Go to workbook and look at the diagram.
A
6
Q
What is the peripheral nervous system?
A
- The PNS consists of a network of nerves that connects the rest of the body to the CNS.
- Information that is sent through the nervous system moves along networks of cells called neurons. These neurons can only send information one way.
7
Q
The CNS and PNS work together to….
A
- Collect information from inside the body and the environment outside it.
- Process the information.
- Execute a response.
8
Q
What is the somatic nervous system?
A
- The SNS receives information from the senses and transmits it to the CNS through sensory neurons (afferent pathways).
- It also transmits information from the CNS to instruct the movement of muscles. Motor neurons carry these instructions (efferent pathways).
9
Q
What is the autonomic nervous system?
A
- The autonomic nervous system is responsible for the vital functions such as heartbeat, breathing, digestion etc.
- It operates automatically and involuntary.
- It is responsible for controlling the “fight or flight” response.
10
Q
What is the sympathetic branch?
A
- The sympathetic branch of the ANS is activated in response to fear/ threat.
- It controls the bodily changes needed to defend ourselves to escape.
- Increased HR, increased BR, pupil dilation, sweat production, reduction of non-essential functions.
11
Q
What is the parasympathetic branch?
A
- The parasympathetic branch of the ANS is responsible for returning our bodies state to normal.
12
Q
What happens to the nervous system during the ‘fight or flight’ response?
A
- A person enters a stressful/ dangerous situation.
- The amygdala (part of the limbic system) is activated which sends a distress signal to the hypothalamus.
- The hypothalamus activates the sympathomedullary pathway (SAM pathway)- the pathway running to the adrenal medulla and the sympathetic nervous system (SNS).
- The SNS stimulates the adrenal medulla, part of the adrenal gland (outside= adrenal cortex, inside= adrenal medulla).
- The adrenal medulla secretes the hormones adrenaline and noradrenaline into the blood stream.
- Adrenaline causes a number of physiological changes to prepare the body for fight or flight.
13
Q
What are the 5 physiological changes that occur due to the sympathetic nervous system during fight or flight?
A
- Increased heart rate.
- Increased breathing rate.
- Pupil dilation.
- Sweat production.
- Reduction of non-essential functions (e.g. digestive system, urination, salivation).
14
Q
Why is there an increase in HR?
A
- To increase blood flow to the organs and increase movement of adrenaline around the body.
15
Q
Why is there an increase in breathing rate?
A
- To increase oxygen intake.
16
Q
Why does pupil dilation occur?
A
- To increase light entry into the eye and enhance vision (especially in the dark).
17
Q
Why does sweat production increase?
A
- To regulate body temperature.
18
Q
Why is there a reduction of non-essential functions?
A
- To increase energy for other essential functions.
