science 5.1 knp pdf

Nervous SystemChapter 5 - Section 1

Nervous System

Nervous System

Any internal or external change that brings about a response is called a stimulus

Nervous System


Noise, light, the smell of food, and the temperature of the air are all stimuli from outside your body.

Nervous System


Noise, light, the smell of food, and the temperature of the air are all stimuli from outside your body.

Chemical substances such as hormones are examples of stimuli from inside your body.

Keeping everything in order


The regulation of steady, life-maintaining conditions inside an organism, despite changes in its environment, is called homeostasis.


The regulation of steady, life-maintaining conditions inside an organism, despite changes in its environment, is called homeostasis.

Examples: Regulating breathingRegulating heartbeatRegulating digestions

Nerve Cells

Neurons are made up of a cell body and branches celled dendrites and axons.

Axons carry impulses away from the cell body. The axon branches at the end to send the signal to many other muscles, neurons, or glands.

Types of Nerve Cells


Motor Neurons ~ Sensory Neurons ~ Interneurons



Sensory neurons – receive information and send impulses to the brian or spinal cord, where…




Interneurons – relay these impulses to…




Interneurons – relay these impulses to…

Motor neurons – conduct impulses from the brain or spinal cord to muscles or glands throughout the body.

Synapses

To move from one neuron to the next, an impulse crosses a small space called a synapse.

Synapses

Synapses

When an impulse reaches the end of an axon, the axon releases a chemical.

Synapses


This chemical flows across the synapse and stimulates the impulse in the dendrite of the next neuron.

Synapses


This chemical flows across the synapse and stimulates the impulse in the dendrite of the next neuron.

Your neurons are adapted in such a way that impulses move in only one direction.

Synapses

The Central Nervous System

The central nervous system is made up of the brain and spinal cord.

CNS – The Brain

CNS – The BrainThe brain coordinates all of your body activities.


Made of 100 billion neurons



WHAT?!?! 100 billion.....

▪That is absolutely.....





And that is only 10% of all the neurons in the human body.





And that is only 10% of all the neurons in the human body.

The brain is surrounded by a bony skull and 3 membranes and a layer of fluid.

CNS – The Brain

CNS – The Cerebrum


The cerebrum is the largest part of brain



This is where…thinking takes place impulses from the senses are interpretedmemory is storedmovements are controlled



This is where…thinking takes place impulses from the senses are interpretedmemory is storedmovements are controlled

The outer layer, called the cortex, is marked by many ridges and grooves (increasing the surface area).

CNS - Cerebellum

CNS - Cerebellum

What is interpreted in the cerebellum? Stimuli from the eyes and earsStimuli from muscles and tendons

CNS - Cerebellum

What is interpreted in the cerebellum? Stimuli from the eyes and earsStimuli from muscles and tendons

The cerebellum interprets this information and uses it to coordinate voluntary muscle movement, maintain muscle tone, and helps maintain balance.

CNS – The Cerebellum

CNS – The Brain Stem

CNS – The Brain StemThe brain stem is located at the base of the brain

and extends from the cerebrum and connects the brain and the spinal cord



Is made up of the midbrain, the pons, and the medulla




The midbrain and pons act as pathways to connect dif ferent parts of the brain with each other.




The midbrain and pons act as pathways to connect dif ferent parts of the brain with each other.

The medulla controls involuntary actions (heartbeat, breathing, blood pressure). It is also involved in actions such as coughing, sneezing, vomiting.

CNS - The Brain Stem

CNS – The Spinal Cord


The spinal cord is an extension of the brain stem.



It contains bundles of neurons that carry impulses between all parts of the body and the brain.



It contains bundles of neurons that carry impulses between all parts of the body and the brain.

An adult spinal cord is about the width of an adult thumb and is about 43 cm long.

The Peripheral Nervous System


Your brain and spinal cord are connected to the body by the peripheral nervous system.


Your brain and spinal cord are connected to the body by the peripheral nervous system.

The PNS is made up of 12 pairs of nerves from your brain called cranial nerves and 31 pairs from your spinal cord called spinal nerves.


Spinal nerves are made of bundles of sensory and motor neurons bound together.



In this way a single spinal nerve can have senses going to and from the brain.



In this way a single spinal nerve can have senses going to and from the brain.

Some nerves contain only sensory neurons, and some contain only motor neurons, but most nerves contain both types of neurons.

PNS – Somatic and Autonomic Systems


Somatic System controls voluntary actions



It is made up of cranial and spinal nerves that go from the CNS to your skeletal muscles.



It is made up of cranial and spinal nerves that go from the CNS to your skeletal muscles.

Autonomic System controls involuntary actions (such as heart rate, breathing, digestion, glandular functions)

Safety and the Nervous System


Any injury to the brain or the spinal cord can be serious.



A severe blow to the head can bruise the brain and cause temporary or permanent loss of mental and physical abilities.



A severe blow to the head can bruise the brain and cause temporary or permanent loss of mental and physical abilities.

Spinal cord injuries can be just as dangerous as a brain injury.


Injury to the spine can bring about damage to nerve pathways and result in paralysis, which is the loss of muscle movement.

Safety - Reflexes

Safety - Reflexes

You experience a reflex when you touch something hot, or when you cough or vomit.

Safety - Reflexes


Reflex – an involuntary automatic response to a stimulus.

Safety - Reflexes



You cannot control them because they occur before you are aware of them.

Safety - Reflexes



You cannot control them because they occur before you are aware of them.

They involve a simple nerve pathway called a reflex arc.

Safety - Reflexes

Safety - Reflexes

Reflexes allow your body to respond without having to think about what action to take.

Safety - Reflexes


Reflex responses are controlled in your spinal cord, not your brain.

Safety - Reflexes


Reflex responses are controlled in your spinal cord, not your brain.

Your brain acts after the reflex to help figure out what to do next to stop the pain.

Drugs and the Nervous System


Many drugs, such as alcohol and caffeine, directly affect your nervous system.


Many drugs, such as alcohol and caffeine, directly affect your nervous system.

When swallowed, alcohol passes directly through the walls of the stomach and small intestine into the circulatory system.

This drug slows the activities of the central nervous system and is classified as a depressant.


This drug slows the activities of the central nervous system and is classified as a depressant.

Heavy alcohol use destroys brain and liver cells.


•Caffeine is another drug that can affect your nervous system.


•Caffeine is another drug that can affect your nervous system.

•Too much caffeine can increase heart rate and aggravates restlessness, tremors, and insomnia in some people.


science 5.1 knp pdf

Health & Medicine

brain coordinates

motor neurons

sensory neurons

body activities

cns cerebellum

types of ner ve cells

cell body

human body