nervous system

Question 1

what is a neuron

Answer 1

-the basic structural and functional unit of the nervous system is the nerve cell or a neuron. A nerve cell has three main parts: cyton, axon, and dendrites
-nerve cells are joined from end to end to form long nerve fibers
- number of nerve fibers ( axon parts) are bundled together in a tubular sheath to form a nerve

Question 2

what are the three types of nerves

Answer 2

-sensory nerves: bring impulses from the sensory organs to the brain or the spinal cord. These contain only sensory fibres. eg:optic nerve
-motor nerve: which carry impulse from the brain or the spinal cord to the muscles or glands. eg: nerves to the eye muscles
-mixed nerves: which carries both fibres. Based on the origin there are two types:
Cranial nerves: which arise from the brainnd reach the organs in the head region,there are 12 pairs
Spinal nerves: Arising from the spinal cord an reach various parts of the body.There are 31 pair in the body.

Question 3

describe the cerebrum

Answer 3

-uppermost and largest part of the brain
-the surface has many grooves and ridges to accommodate numerous nerve cells.
- it is divided into the right and left parts known as the cerebral hemispheres
-controls mental activities like thinking
-center for intelligence and memory
-centre centre for perceiving pain, sound, touch ,taste, and smell

Question 4

describe the cerebellum

Answer 4

-small portion located under the cerebrum at the back of the head
-has many furrows but lacks convolutions
-it is also divided into two cerebral hemispheres
-maintains balance of the body
-coordinates muscular activities of our body

Question 5

describe the medulla oblangata-

Answer 5

-lowest part of the brain
-joins the brain to the spinal cord
-located at the base of the skull above the spinal cord
-controls the vital activity of internal organs like heartbeat, breathing, and other involuntary moments.

Question 6

describe the spinal cord

Answer 6

-starts at the medulla oblongata and runs down the whole vertebral column
-the vertebral column protects it
-conducts messages from the skin and muscles to the brain
-to conduct messages or commands from the brain ti the muscles of the body trunk and limbs
-central canal contains cerebrospinal fluid
-central canal is surrounded by an H shaped area known as grey matter
-grey matter is made up of cell bodies of neurons
-the outer part is called white matter which is made up of nerve fibres

Question 7

what are stimulus

Answer 7

any change in the environment of an organism that results in a change in the activity of the body is called stimulus.

Question 8

what is a response

Answer 8

any activity due to the stimulus is called response

Question 9

what is a receptor

Answer 9

sense organs detect a stimulus and transmit the stimulus through the nerves to CNS.

Question 10

what is an effector

Answer 10

any muscle or organ after receiving the impulse from the brain or the spinal cord, responses to the stimulus

Question 11

what is a motor neuron

Answer 11

-located in the cns
-axons are projected outwards to directly or indirectly control the muscles
-multi polar which means it has one axon and multiple dendrites
-recieves info from other neurons and and conveys the information to the muscles

Question 12

what is the flowchart of a reflex actions

Answer 12

stimulus -recceptor organ - sensory neurons -spinal nerves -motor neurons - muscle action -response

Question 13

what are reflex actions?

Answer 13

the actions controlled by the spinal cord are known as the reflex actions.

Question 14

what is the sequence of events that occur when the hand touches a hot object?

Answer 14

-the heat of an object (stimulus) stimulates the nerve endings in the skin (receptor)
-as a result impulses are produced which travel through the sensory neuron to the spinal cord.
-in the spinal cord the impulses are transmitted to another neuron
-the response travels from the spinal cord along the motor neuron to the effector
-the effector which is muscle then contracts causing the sudden with drawal of the hand

Question 15

what are the different types of nerves

Answer 15

-sensory-eyeball
-motor nerves to the eye muscle
-mixed nerves in the tongue
-mixed are further divided into cranium and spinal

Question 16

what do the peripheral and central nervous system contain

Answer 16

-central nervous system contains the spinal cord and brain
- the peripheral nervous system contains the cranial nerves and spinal nerves

Question 17

what is the cns and pns composed of

Answer 17

-cns is composed of brain spinal cords and relay neurons
-pns is composed of cranial nerves, spinal nerves, peripheral nerves, motor neurons and sensory neurons

Question 18

what are meninges

Answer 18

The MENINGES refers to the three membranous
covering which protects the brain and the spinal
cord.The three layers include the dura mater,
arachnoid mater, and the pia mater.The
meninges protects the organs of the central
nervous system namely the brain and the spinal
cord from mechanical injury. It provides
anchorage to the brain and prevents it from
moving inside the skull.

Question 19

what is the forebrains function

Answer 19

-processes sensory info
-reasoning and logic, problem solving
-autonomic,endocrine and motor functions

Question 20

what is the hindbrains function

Answer 20

-autonomic functions
-relay sensory info
-coordinate movement
-maintain equilibrium
-

Question 21

what is the midbrains function

Answer 21

-regulate movement
-auditory and visual info

Question 22

what is the cell body

Answer 22

The cell body in a nerve cell is its core. It is also called soma.
● The cell body consists of the nerve cell’s nucleus along with other specialised cell
organelles such as the endoplasmic reticulum, Golgi apparatus, mitochondria, and
other components.
● It helps in maintaining the cell’s overall structure and provides energy to carry out
the cell’s activities.

Question 23

what are dendrites

Answer 23

Dendrites are root-like projections on a cell body that facilitate the transmission and
receiving of messages to and back from other neurons

Question 24

what is the axon

Answer 24

An axon is a part of the nerve cell, which is a long tube-like structure that joins the
cell body at a specific position.
● It is primarily involved in carrying the electrical signals from the cell body to the
neuron ending and transmitting it to other surrounding neurons.

Question 25

what is the myelin sheath

Answer 25

It is the outermost layer of a nerve cell.
● Its primary function is to cover and protect the nerve fibres in the neurons.

Question 26

what is the node of ranvier

Answer 26

Nodes of Ranvier are located between sheaths of myelin.
● These are basically gaps formed between the myelin coating (sometimes called
myelin sheath gaps), and are the only parts of axon that are uninsulated.
● They facilitate speedy electric transmission.