Biology NERVOUS SYSTEM
Introduction
The Nervous system controls:
Sight, hearing, taste, smell, and feeling (sensation)
Voluntary and involuntary involuntary functions, such as movement, balance, and coordination. The nervous system also regulates the actions of most other body systems, such as blood flow and blood pressure.
The ability to think and reason. The nervous system allows you to be conscious and have thoughts, memories, and language.
Definitions of words
Stimulus (plural stimuli): detectable change in internal or external environment Response: reaction of organism to stimuli Receptors: sense organs or sensory nerve endings, that receive impulse Effectors: muscle or gland, that responds to impulse received
Table showing the Stimulus that various Receptors detect Receptors
Stimulus they detect
Eye Nose Ear Tongue Skin
Pressure/Heat/Cold
Response of Plants to unilateral light
Nervous System of Humans
The nervous system can be divided into two main categories •
•
1. Central Nervous system (CNS): brain and spinal cord
2. Peripheral Nervous system (PNS): branches off from CNS
Nervous system
The basic unit or cells that makes up the nervous system are called Neuron (also Neurone) They are: Cells of the nervous system, called nerve cells or neurons, neurons, that are specialized to carry "messages" through an electrochemical process (electrical and chemical method of carrying message)
Neur Ne uron onss- St Stru ruct ctur uree
Annotated Annotat ed diagram of a Neuron
Neurons
Neurons are specialized cells that conduct nerve impulses. There are three basic types 1. Sensory Neuron: carry impulse from receptors (sense cells) to CNS
Diagram of a sensory neuron
2 Relay/ Intermediate Neuron: found in CNS
Types of Neurons
3. Motor Neuron: carry impulse form CNS to effectors (muscles or gland)
Review
Nervous system receives, interprets and respond to stimulus Two categories :CNS, PNS Neurons are basic units ; three types
Sensory: receptor to CNS Intermediate/relay: Intermediate/relay: found in CNS Motor: CNS to effectors
Reflex action
Quick, automatic and involuntary response Requires not thought or learning e.g. knee jerk, pupil reflex or removing hand from a hot plate Brain is not involved (unless its cranial reflex)
Reflex action
Video- Reflex arc
Reflex arc video 2
Neurotransmitters
Neuron carry messages/impulse as both electrical and chemical energy Along axon- electrical impulse At gap (synapse), chemicals called called Neurotransmitters allows impulse to travel across the synapse
Neurotransmitter Neurotransmitt er at Synapse
Brain-Structure and Function
Cerebrum/Cerebral hemisphere
Controls voluntary actions Controls memory, reasoning, judgment, intelligence, speech, and learning
Brain-Structure and Function
Cerebellum Coordinate body movement (walking, running) posture, and balance
Medulla Oblongata
Controls involuntary actions such as breathing rate, heart rate, and regulation of body temperature temperature
Structure of a Human Brain
Problems of Nervous system
1. Stroke: a lack of blood to part of the brain
Problems of the Nervous System
Parkinson’s disease
death of neurons in a part of the brain called the midbrain. Symptoms include shaking and problems with movement –
Problems of the Nervous System
Paralysis is the loss of muscle function in part of your body. It happens when something goes wrong with the way messages pass between your brain and muscles.
Summary
The nervous system allows us to receive stimulus, process it, and then respond Made up of : CNS and PNS Basic cells are called Neurons Impulse (messages) are carried by electrical and chemical processes Cerebellum controls body movement, medulla oblongata controls body functions and cerebrum controls voluntary actions Reflex arc Problems of Nervous system
Quiz
The part of the brain in charge of thinking and memory. A. cerebrum B. cerebellum C. medulla oblongata
Question 2
This is made up of the brain and spinal cord. A. peripheral nervous system B. central nervous system C. enteric nervous system
Question 3
Nerve cell are called A. cerebrum B. cerebellum C. neuron
Question 4
The major organ of the nervous system encased in the skull. A. neuron B. axon C. brain C. brain
Question 5
An axon conducts nerve impulses _________ the cell body. A)away A)away from B)toward B)toward C) both toward toward and away away from D)around, D)around, bypassing
Question 6
Which of the following following is/are type(s) of neurons? A)sensory A)sensory B)motor B)motor C)interneurons C)interneurons D)all D)all of the above
Question 7
Which is not the part of the brain? A.Cerebrum B.Cerebellum C.Medulla D.Spin D.Spinal al Chord Chord
Question 8
The three main parts of the neuron are the A.dendrites, cell body and axon axon
B.axon, dendrites and synapse.
C.synapse, impulse and cleft.
D.myelin sheath, dendrites and synapse. synapse.
Question 9
For a student to recall his/her integrated science notes, action must take place in A. a reflex arc B. the cerebrum C. the cerebellum D. the medulla oblongata
Question 10
Which of the following following shows the correct path of impulse in a reflex arc A. motor neuron neuron sensory neuron relay neuron
B. sensory neuron motor neuron relay neuron
C. motor neuron relay neuron sensory neuron
D. sensory neuron relay neuron motor neuron
Answer to question question 10
THE END!!
Slides prepared by: by: Muhamad Nabeel Uddin
Please check my my profile here http://www.scribd.com/nabeel_uddin for more CSEC Biology and Integrated Integrated Science PowerPoint presentations.
