Human Nervous System Flashcards
What are the 2 types of coordination?
The 2 types are:
- Nervous
- Chemical
What is nervous coordination?
this is brought about by the nervous system, which is made up of the brain, spinal cord, nerves and sense organs.
ex- when you feel hungry you eat
What is chemical coordination?
this type of coordination is brought about by the chemical messengers called hormones.
ex- when you see a bull on the street your instinct is to run. chemicals release extra energy in the blood to help you run
Structural and Functional Unit of Nervous System - NEURON
- nervous system is made up of cells called nerve cells or neurons
- it is made up of a cyton and an axon
- it contains of a nucleus
- dendrites receive impulses from organs and transmit them to axon
- end of axon has a number of branches called axon terminals or terminal branches
Structural and Functional Unit of Nervous System - NEURON
- nervous system is made up of cells called nerve cells or neurons
- it is made up of a cyton and an axon
- it contains of a nucleus
- dendrites receive impulses from organs and transmit them to axon
- end of axon has a number of branches called axon terminals or terminal branches
What is synapse?
the axon terminals of a neuron lie very close to the dendrites of another. their point of contact is called synapse it is at this place where the message is transmitted .
What are the 3 types of neurons?
- sensory neurons
- motor neurons
- association neurons
Explain the 3 types of neurons
- SENSORY: these carry impulses from the sense organs to the spinal cord or brain
- MOTOR: these carry impulses from brain or spinal cord to the source [ muscle ]
- ASSOCIATION: these are present in the spinal cord and transmit impulses from one neuron to another
What is a nerve? what are its 3 types?
a nerve is formed of a bundle of axons enclosed in a tubular medullary sheath. its types - sensory nerve - motor nerve - mixed nerve
Explain the 3 types of nerves
- SENSORY: consists of sensory neuron ex- optic nerve - MOTOR: contains only motor neurons ex- muscle of the eye -MIXED: carries both, sensory and motor neurons ex- nerve going to the tounge
What are the 2 main systems in the human nervous system?
- The central nervous system
2. The peripheral nervous system
Explain these 2 systems: central and peripheral
- This consists of the braina and spinal cord. Brain lies within the skull and the spial cord lies within the vertebral column.
- It consists of nerves that pass to and from the central nervous system. Its 2 parts are:
~ somatic nervous system
~ autonomic nervous system
Give a brief about our brain
- it is the complex and important part of our body
- on an average an adult brain weighs 1.5kg
- it is protected by a bony structure called skull or cranium
- brain is further divided into 3 membranes called meninges which are separated by the fluid floating around in our brain
Name the 3 main parts of the brain
- cerebrum
- cerebellum
- medulla oblongata
Explain cerebrum
- it is the largest portion of the brain
- it is divided into 2 hemispheres called the cerebral hemispheres
- each of these are hollow
- outer surface is covered with bridges and grooves to accommodate many neurons
- human cerebrum contains about 9B neurons
- this controls all the voluntary actions
ex- intelligence , will power , consciousness
Explain cerebellum
- it is smaller and is under the cerebrum
- its main function is to balance the body and coordinate muscular activities
- cerebellum implements the action that the cerebrum decides
- a drunk person cannot coordinate his movements properly as alcohol affects the cerebellum
Explain medulla oblongata
- it is the lowest part
- it controls the activities of internal organs
ex- beating of heart , breathing - if this is seriously injured it may cause immediate death of a person
Give a brief about spinal cord
it extends from the medulla through the whole backbone
What is the spinals cords main functions
- control reflexes below the neck
- carry messages from skin , muscle to brain
- conduct commands from brain to muscle of the trunk limbs
Give brief about peripheral nervous system
its divided into somatic and autonomic nervous system.
Define somatic nervous system
- they consist of 2 types of nerves:
~cranial nerves which arise from the brain
~spinal nerves which arise from the spinal cord - it is responsible for relaying sensations like smell , taste , etc
- and also for sending commands from central nervous system to skeletal muscles
Define autonomic nervous system
- it consists of a pair of chains of ganglia
- it regulates involuntary actions and works unconsciously
ex- blood pressure , respiratory rate - it operates through 2 systems:
~ sympathetic system
~ parasympathetic system
Define sympathetic system
- this produces immediate flight or fight responses
What is parasympathetic system
- this re-establishes normal conditions
ex- if sympathetic system increases heart rate then parasympathetic will relax it
