THE HUMAN NERVOUS SYSTEM
Coordinating systems = structures that allow communication between
receptors and effectors so that the correct reaction to any change in the
environment can be brought about
The following systems work together to respond to changes in environ +
control conditions inside body:
❏ NERVOUS CO-ORDINATING SYSTEM
❏ Fastest response
❏ Brought about by impulses traveling along nerves
❏ ENDOCRINE CO-ORDINATING SYSTEM
❏ Slower
❏ Brought abt by chemicals [hormones] carried by blood
FUNCTION OF THE NERVOUS SYSTEM:
1. SENSORY FUNCTION
a. Sensory receptors detect changes in external environ + body
2. INTEGRATIVE FUNCTION
a. Central nervous system [CNS] receives info, then decides
which effectors should react to the stimulus
b. Integrates the sensory input
3. MOTOR FUNCTION
a. Effectors [muscles + glands] bring about movement
STIMULI:
Stimuli = physical/chemical changes in internal/external environ that can
cause a response in an organism
External: light, temp, touch, sound, atmospheric pressure
Internal: blood pressure, blood pH, muscle tension
THE HUMAN NERVOUS SYSTEM
Divided into the Central nervous system [CNS] / Peripheral nervous
system [PNS]
, THE CENTRAL NERVOUS SYSTEM
❏ Made up of a concentrated mass of interconnected neurons (nerve
cells) grouped together to form:
❏ Brain
❏ Spinal cord
❏ Both = responsible for processing all info from senses + keeping
organs & reflexes functioning + directing movements, thoughts &
feelings
PROTECTION OF THE CENTRAL NERVOUS SYSTEM
❏ Protected by meninges [3 connective tissue membranes]
❏ Cerebro-spinal fluid fills space between 2nd & 3rd layer of meninges
❏ Shock absorber + prevents damage, acts as a pillow
❏ CSF = fluid formed from blood plasma in special areas in the
walls of the ventricles
CNS + meninges = enclosed in bony case of 2 structures:
❏ Cranium
❏ Strong, dome-shaped
❏ Protects brain from mechanical injuries
❏ Made up of 8 curved skull bones joined by fibrous joints called
sutures
❏ vertebral column
❏ Made up: 33 irregular vertebrae
❏ Surrounds + protects spinal cord from mechanical injury
❏ S-shaped curve of vertebral column + cartilaginous discs :
❏ Prevent jarring of the CNS
❏ Give body spring + resilience
1. THE BRAIN
- Enlarged upper part of spinal cord
- Enclosed by cranium
Coordinating systems = structures that allow communication between
receptors and effectors so that the correct reaction to any change in the
environment can be brought about
The following systems work together to respond to changes in environ +
control conditions inside body:
❏ NERVOUS CO-ORDINATING SYSTEM
❏ Fastest response
❏ Brought about by impulses traveling along nerves
❏ ENDOCRINE CO-ORDINATING SYSTEM
❏ Slower
❏ Brought abt by chemicals [hormones] carried by blood
FUNCTION OF THE NERVOUS SYSTEM:
1. SENSORY FUNCTION
a. Sensory receptors detect changes in external environ + body
2. INTEGRATIVE FUNCTION
a. Central nervous system [CNS] receives info, then decides
which effectors should react to the stimulus
b. Integrates the sensory input
3. MOTOR FUNCTION
a. Effectors [muscles + glands] bring about movement
STIMULI:
Stimuli = physical/chemical changes in internal/external environ that can
cause a response in an organism
External: light, temp, touch, sound, atmospheric pressure
Internal: blood pressure, blood pH, muscle tension
THE HUMAN NERVOUS SYSTEM
Divided into the Central nervous system [CNS] / Peripheral nervous
system [PNS]
, THE CENTRAL NERVOUS SYSTEM
❏ Made up of a concentrated mass of interconnected neurons (nerve
cells) grouped together to form:
❏ Brain
❏ Spinal cord
❏ Both = responsible for processing all info from senses + keeping
organs & reflexes functioning + directing movements, thoughts &
feelings
PROTECTION OF THE CENTRAL NERVOUS SYSTEM
❏ Protected by meninges [3 connective tissue membranes]
❏ Cerebro-spinal fluid fills space between 2nd & 3rd layer of meninges
❏ Shock absorber + prevents damage, acts as a pillow
❏ CSF = fluid formed from blood plasma in special areas in the
walls of the ventricles
CNS + meninges = enclosed in bony case of 2 structures:
❏ Cranium
❏ Strong, dome-shaped
❏ Protects brain from mechanical injuries
❏ Made up of 8 curved skull bones joined by fibrous joints called
sutures
❏ vertebral column
❏ Made up: 33 irregular vertebrae
❏ Surrounds + protects spinal cord from mechanical injury
❏ S-shaped curve of vertebral column + cartilaginous discs :
❏ Prevent jarring of the CNS
❏ Give body spring + resilience
1. THE BRAIN
- Enlarged upper part of spinal cord
- Enclosed by cranium
