Unit 3 Lesson 5 The Nervous and Endocrine Systems Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 3 Lesson 5 The Nervous and Endocrine Systems

Copyright © Houghton Mifflin Harcourt Publishing Company


Florida Benchmarks


• SC.6.L.14.5 Identify and investigate the general functions of the major systems of the human body (digestive, respiratory, circulatory, reproductive, excretory, immune, nervous, and musculoskeletal) and describe ways these systems interact with each other to maintain homeostasis.

• HE.6.C.1.4 Recognize how heredity can affect personal health.


Florida Benchmarks


• HE.6.C.1.8 Explain how body systems are impacted by hereditary factors and infectious agents.

Brainiac!


What is the function of the nervous system?• The nervous system is made up of the structures

that control actions and reactions of the body in response to stimuli in the environment.

• The nervous system has two parts: the central nervous system (CNS) and the peripheral nervous system (PNS).


What is the function of the nervous system?• The CNS is made up of the brain and spinal cord.

• The brain is the body’s central command organ.

• The spinal cord allows the brain to communicate with the rest of the body.



What is the function of the nervous system?• The PNS connects the CNS to the rest of the body.

• Involuntary processes are those you have no control over, such as your heart beating.

• Voluntary processes are actions your brain can control, such as moving an arm or leg.



What are the parts of the CNS?

• The CNS is made up of the brain and the spinal cord.

• The cerebrum is the largest part of the brain. It is where you think, solve problems, and store memories.

• The cerebrum controls voluntary movements and processes information from your senses.




• The cerebellum processes information from your body, keeps track of body position, and coordinates movements.

• The brain stem connects your brain to the spinal cord.

• A part of the brain stem called the medulla controls involuntary processes in the body.




• Describe the part of the brain that made one activity that you did today possible.




• The spinal cord is a bundle of nerves protected by bones called vertebrae.

• Nerves are a collection of nerve-cell extensions bundled together with blood vessels and connective tissue.

• The spinal cord carries messages to and from the brain.



You’ve Got Nerves!


How do signals move through the nervous system?• The nervous system translates environmental

information into electrical signals.

• A neuron is a special cell that moves messages in the form of fast-moving electrical energy. These messages are called impulses.


How do signals move through the nervous system?• Signals move through the CNS and PNS with the

help of glial cells that protect and support neurons.

• Sensory neurons gather information from in and around your body and move it to the brain.

• Motor neurons move impulses from the brain and spinal cord to other parts of the body.



What are the parts of a neuron?

• The cell body of a neuron has a nucleus and organelles.

• A dendrite is a typically short, branched extension of the cell body.

• The cell body gathers information from dendrites and creates an impulse.




• An axon is an extension of the neuron that carries impulses away from the cell body.

• A neuron has only one axon.

• At the end of the axon is the axon terminal that changes the electrical signal to a chemical signal, or neurotransmitter.




• How is a message transformed from an electrical message to a chemical message in a neuron?



That Makes Sense!


What are the main senses?

• The sensory organs sense the environment around you.

• Sight allows you to see objects, motion, and light.


That Makes Sense!



• The main parts of the eye include the cornea, pupil, retina, and rods and cones.

• Light-sensitive receptors in the retina change light into electrical impulses that are sent to the brain.



• Impulses travel to your brain, creating an awareness of touch called a sensation.

• Hearing happens when sound-wave vibrations are turned into electrical impulses in the ear.

• Sound is funneled through the outer ear, making the eardrum vibrate.




• Tiny bones in the ear vibrate, causing the fluid in the cochlea to move in waves.

• Hair cells in the fluid causes neurons to send electrical impulses to the brain via the auditory nerve.

• Taste cells in the mouth and olfactory cells in the nose send signals to the brain for processing taste and smell.



Keep Your Cool!


What is the function of the endocrine system?• The endocrine system controls body functions

and helps maintain homeostasis by using hormones.

• A hormone is a chemical messenger made in one cell or tissue that causes a change in another cell or tissue elsewhere in the body.


How do hormones work?

• Hormones are produced by endocrine glands or tissues and travel through the bloodstream.

• A gland is a group of cells that make special chemicals in your body.

• Hormones only affect specific target cells that have a specific receptor to that hormone.



What glands make up the endocrine system?• The pituitary gland secretes hormones that control

other glands.

• The hypothalamus controls the release of hormones from the pituitary gland.

• The pineal gland makes hormones that control sleep, aging, reproduction, and body temperature.



What glands make up the endocrine system?• The thyroid gland controls metabolism.

• The parathyroid gland controls calcium in the blood.

• Reproductive hormones control reproduction.

• The pancreas regulates blood-sugar levels.



Feedback


How are hormone levels controlled?

• The endocrine system helps maintain homeostasis by increasing or decreasing hormone levels.

• The endocrine system uses feedback to maintain homeostasis.


How are hormone levels controlled?

• A feedback mechanism is a cycle of events in which information from one step controls or affects a previous step.

• In negative feedback, the effects of a hormone cause the release of that hormone to be turned down.

• In positive feedback, the effects of a hormone stimulate the release of more of that hormone.



What are disorders of the endocrine and nervous systems?• Hormone imbalances can happen when the

endocrine system makes too much or too little of a hormone.

• Type 1 diabetes is caused by a hormone imbalance.

• Parkinson’s disease, multiple sclerosis, and spinal-cord injuries are disorders of the nervous system.



Documents

Unit 3 Lesson 5 The Nervous and Endocrine Systems Copyright © Houghton Mifflin Harcourt Publishing Company