Responding to the environment

Question 1

What are co-ordinating systems

Answer 1

system allows communication between the receptors and effectors of the body so that correct reactions can be brought about
the nervous co-or. system responds fastest and is brought about by impulses traveling along nerves

Question 2

what are the functions of the nervous and endocrine co-ordinating systems

Answer 2

work together to respond to environmental changes and control conditions inside the body

Question 3

What is the nervous system responsible for

Answer 3

it is the bodies control and communication centre
providing continuous flow of info.
it enables the body to function in an orderly way

Question 4

how does the nervous system function

Answer 4

Sensory function- sensory receptors detect change in the external and internal environment

Integrative function- central nervous system receives this info. and identifies which effectors need to react to stimulus

motor function - effectors (muscles and glands) respond appropriately
[stimuli are physical or chemical changes in the environment, capable causing response in an organism]

Question 5

What is the Central Nervous System responsible for [3]

brain and spinal cord

Answer 5

1 processing all information coming from senses
2 keeping our organs and reflexes functioning
3 directing movements, thoughts and feelings

Question 6

How is the CNS protected and nourished

Answer 6

by three connective tissue membranes ( meninges )
- space between the second and third layer has cerebro-spinal fluid acting as a cushion against shock/damage

as well as a bony case made up of two separate structures

1. Cranium for mechanical injuries + made up of 8 curved skull bones placed firmly together by sutures
2. Vertebral column made up of 33 irregular shape vertebrae around spinal cord

Question 7

What is the purpose of cartilaginous discs, joints and the S-shaped spinal cord

Answer 7

prevents jarring of the CNS by giving the body spring and resilience

Question 8

what holds the two cerebral hemispheres of the cerebrum together

Answer 8

between the longitudinal fissure is a mass of myelinated nerve fires - Corpus callosum

Question 9

what is the function of the corpus callosum

Answer 9

provides for communication between cerebral cortex and lower parts of the CNS enabling them to function as a whole

Question 10

why is the cerebrum folded and grooved

Answer 10

enlarges the surface are so large amounts of brain cells can fit in the cranial cavity
deeper folds divide the brain into 4 lobes
grooves- sulci
folds- gyri

Question 11

what are the cavities within the brain called and what are they filled with

Answer 11

ventricles and cerebro-spinal fluid

Question 12

Where is the cerebral cortex located and what is it made up of

Answer 12

outer 3mm of the cerebrum
made up of a collection of cell bodies neurons (grey matter)
below the grey matter is white matter (myelinated nerve fibres)

Question 13

List 3 functions of the cerebrum

Answer 13

1. motor area
   - frontal lobe where voluntary movements of body originate
2. sensory area
   - receive and interpret impulses from sense organs [hearing, tasting, skin sensations and sight]
3. association cortex
   - higher mental activities [intelligence, language and consciousness]

Question 14

Describe the location and structure of the cerebellum

Answer 14

location- behind and below cerebrum
made up of two hemispheres
white matter looks like branches with grey matter surrounding it = where ‘tree of life’ name came from

Question 15

What are the 3 functions of the cerebellum

Answer 15

1. co-ordinate the actions of voluntary muscles= smooth and controlled physical actions
2. muscle tone
3. posture and balance by using info. from inner ear

Question 16

Describe the structure of medulla oblongata

Answer 16

forms the lowest part of the brain stem and passes through the foramen magnum (big hole) at base of the cranium for the spinal cord.

Question 17

State 3 functions of the medulla oblongata

Answer 17

1. pathway for impulses between brain and body
2. reflex centre [breathing, heart beat, blood pressure and swallowing + peristalsis]
3. controls less important reflexes e.g. sneezing

Question 18

What is the spinal cord

Answer 18

an elongated rod of nervous tissue extending from the medulla oblongata through the foramen magnum + situated in vertebral canal of vertebral column
[ 45cm long]

Question 19

Briefly describe the structure of the spinal cord

Answer 19

• has an H-shaped central area of grey matter [nerve cell bodies, dendrites and synapses]
• white matter surrounds this [made of axons and myelin sheaths]
• central canal runs down from ventricles of brain and holds the cerebro-spinal fluid [ is in the centre of the grey matter]
• pair of spinal nerves enter and leave the cord between successive vertebrae (31 pairs)spinal nerves have dorsal roots which enter the grey matter and ventral roots leaving it
• dorsal root has collection of neuron cell bodies [ganglion]

Question 20

name two functions of the spinal cord

Answer 20

1. pathway for impulses
2. seat of primitive reflex actions [ spinal reflexes to protect body e.g. knee jerk reflex] therefor it has an integrative function

Question 21

What is the PNS

Answer 21

all the nervous tissue outside the CNS
linking CNS to receptors and effectors of body
(43 pairs)
12 cranial nerves = sensory and motor nerves [afferent and efferent]
and 31 pairs spinal nerves

Question 22

What are the 2 functions of the PNS

Answer 22

1. Sensory function by collecting info. from receptors via impulses along afferent neurons to CNS
2. Motor function by transmitting impulses from CNS to effectors via efferent neurons to respond appropriately

Question 23

How is the motor division of the PNS made up

Answer 23

1. Somatic nervous system

2. Autonomic nervous system

Question 24

State the differences between the somatic [4] and autonomic nervous system [4]

Answer 24

SOMATIC
>motor unit is single neuron
>the cell body of the neuron is in the CNS and the axon
extends to the effector
>no ganglia in motor division
>effectors are voluntary, skeletal muscles

AUTONOMIC
>motor unit is a two chain unit
>cell body of first motor neuron is in the CNS and its axon synapses with the second neuron in a ganglion outside the CNS
>postganglionic axon extend to effector
>effectors are smooth, involuntary muscle, cardiac
muscle and glands

Question 25

What is the Autonomic nervous system made up of

Answer 25

The parasympathetic and sympathetic nervous system

Question 26

State the structural differences between the parasympathetic and sympathetic nervous system

Answer 26

PARASYMPATHETIC

• motor neuron leaves CNS from brain and sacral region of spinal cord
• ganglia are in wall of effector ( pre-ganglionic fibres long and post-ganglionic fibres short)

SYMPATHETIC

• motor neurons leave CNS from thoracic and lumbar regions of spinal cord
• ganglia close to spinal cord [pre- gang fibres short and post-gang fibres long]

Question 27

What is the function of the sympathetic nervous system

Answer 27

works together with adrenalin in emergency situations causing stress requiring fight or flight
stimulation by these nerves = more oxygen, glucose and blood sent to skeletal muscles for cellular respiration to release more energy for action

Question 28

What is the function of the parasympathetic nervous system

Answer 28

enables body to rest and recover from sympathetic stimulation until back to normal state

Question 29

What is double innervation

Answer 29

most organs are innervated by sympathetic and parasympathetic fibres

Question 30

What is the name of the opposing effects of the para and sympathetic nervous system

Answer 30

effects are antagonistic