ch13 - organisation of the nervous system

what is the nervous system and what is its function

consist of neurones (specialised nerve cells) that:

detect changes in internal and external environment & coordinate bodily functions

-info along neurones = via electrical impulses

-info across neurones = via chemical neurotransmitters

What are the two main parts the Nervous system is divided into?

central nervous system

peripheral nervous system

What is the structure of the CNS/ what does it consist of?

brain - center of conscious awareness

spinal cord - responsible for reflex actions & passes messages to and from brain to PNS

» relay neurones/ inter neurones

What is the function of the CNS?

processes stimuli detected by sensory receptors and decides what to do by coordinating a response

What is the structure of the PNS/ what does it consist of?

Sensory, motor neurones

What is the function of the PNS?

To communicate from the CNS to the rest of the body

-sends information from to CNS & transmits messages from CNS to muscles and glands

What are the further divisions in the PNS branch?

somatic nervous system (SNS)

autonomic nervous system (ANS)

What is the SNS responsible for?

controls conscious and voluntary muscle movements

What is the ANS responsible for?

controls automatic and involuntary responses e.g. breathing, heart rate

Why does our nervous system mostly operate involuntarily?

To let brain focus on more complex responses

 What are the further divisions of the ANS?

Sympathetic

Parasympathetic

What effect does the sympathetic NS have on activity levels?

It increases activity levels and activates the fight or flight response to prepare body for potential danger

What does sympathetic NS having shorter neurone pathways mean?

faster responses

3 Examples of changes which occur due to sympathetic NS?

-dilate pupils to let more light in

-inhibit saliva

-increases heartbeat causing muscles to tense up

What neurotransmitter is used by sympathetic NS?

Adrenaline

Noradrenaline

What effect does the parasympathetic NS have on activity levels?

It decreases activity levels and activates rest and digest response bringing the body back to a calm state 

What does parasympathetic NS having longer neurone pathways mean?

Slower responses

3 Examples of changes which occur due to parasympathetic NS?

-constrict pupils

-secrets saliva

-decreased heartbeat causing muscles to relax

What neurotransmitter is used by parasympathetic NS?

Acetylcholine

what relationship do parasympathetic and sympathetic NS have

antagonistic - have opposing modes of action