YKSD Biology Key Points

Chapter 8 "Human Body Systems"

 

Lesson 1 "How the Body Digests Food"

 

Key Vocabulary Terms

• Peristalsis - the movement of digestive organs that pushes food through the digestive tract.
• Chyme - partly digested liquid food in the digestive tract.
• Gallbladder - the digestive organ that stores bile
• Bile - a substance mad in the liver that breaks down fats.
• Villi - Tiny fingerlike structures in the small intestine through which food molecules enter the blood.
• Feces - solid waste material remaining in the large intestine after digestion
• Rectum - lower part of the large intestine where feces are stored

Key Concepts

• The digestive system breaks down food for your body to use.
• Digestion begins inside the mouth. teeth and jaws chew and crush food, while the tongue turns it over. Enzymes in the saliva begin to break down carbohydrates into sugars.
• In the digestive system, food moves from the mouth, to the pharynx, to the esophagus, to the stomach, and to thee small intestine. Undigested food move to the large intestine and then out of the body through the rectum.
• The shape of villi makes the surface area of the intestine larger. Many food molecules can be absorbed through the blood vessels of the villi.
• Feces leaves the body when smooth muscles in the large intestine contract and push feces out of the body through the anus.

 

Did you learn these Objectives?

• Are you able to trace the path of food through the digestive system.
• Can you tell how and where digestive chemicals act on food?
• Are you able to describe what happens to undigested food?

 

 

Lesson 2 "How Materials Move to and from Cells"

 

Key Vocabulary Terms

• Cardiac - relating to the heart
• Aorta - a large vessel through which the left ventricle sends blood to the body
• Artery - a blood vessel that carries blood away from the heart
• Capillary - a blood vessel with a wall one cell thick through which oxygen and food molecules pas to body cells
• Vein - a blood vessel that carries blood to the heart.
• blood pressure - the force of blood against the walls of blood vessels.
• Plasma - the liquid part of blood.
• Antibody- A protein in plasma that fights disease
• Hemoglobin - A substance in red blood cells that carries oxygen
• Platelet - A tiny piece of cell that helps form clots

 

Key Concepts

• The two main parts of the circulatory system are the heart and the blood vessels.
• Arteries carry blood away from the heart; veins carry blood to the heart.
• Blood has many functions, it: delivers oxygen and carries wastes to the lungs ; delivers nutrients from the digestive system to cells; carries waste products to the kidneys; and contains materials that fight infections and heal wounds.
• The components of the blood are: red blood cells that carry oxygen; white blood cells that fight disease; and platelets that help blood to clot.
• If you are given blood that is of the wrong type it may clump and you will die.

 

Did you learn these Objectives?

• Are you able to identify the major parts of the circulatory system and their functions?
• Can you tell how arteries nd veins are alike and different?
• Can you trace the flow of blood through the heart?
• Are you able to describe the parts of the blood and explain their functions?

 

 

 

Investigation 8 "How Does Exercise Change Heart Rate?" (Optional, must complete 10 total investigations)

Key Concepts and Objectives

• You will use your skills of measuring, observing, collecting and interpreting data, inferring, and recognizing to find out if a heart beats faster when you're very active.
• You will observe the changes in your heart rate during different amounts of activity.

 

 

 

Lesson 3 "How We Breathe"

 

Key Vocabulary Terms

• Pharynx - the passageway between the mouth and the esophagus for air and food.
• Larynx - the voice box
• Trachea - the tube that carries air to the bronchi
• Bronchus - a tube that connects the trachea to a lung (plural is bronchi)
• Bronchiole - a tube that branches off the bronchus.
• Alveolus - a tiny sac at the end of each bronchiole that holds air (plural is alveoli)

 

Key Concepts

• The respiratory system gets oxygen into the body and get rid of carbon dioxide.
• When air comes into the body it moves from the nose to the pharynx, to the larynx, to trachea, to the bronchioles, and to the alveoli.
• Respiration is the exchange of carbon dioxide and oxygen.
• Respiration takes place in the capillaries that surround the alveoli. Oxygen that is breathed in moves through the walls of the alveoli and into the blood. Carbon dioxide from the blood passes out of the capillaries into the alveoli and is exhaled.
• When you inhale, the diaphragm contracts and moves down. When you exhale, the diaphragm relaxes and moves up.

 

Did you learn these Objectives?

• Are you able to identify the function and parts of the respiratory system.
• Can you describe the process of gas exchange in the lungs.
• Are you able to explain how the diaphragm moves when a person breathes.

 

 

 

Lesson 4 "How the Body Gets Rid of Wastes"

 

Key Vocabulary Terms

• Epidermis - the thin outer layer of skin
• Dermis - the thick layer of cells below the epidermis
• Fatty layer - Protects organs, keeps in heat.
• Perspiration - liquid waste made of heat, water, and salt released through the skin.
• Excretory system - a series of organs that get rid of cell wastes in the form of urine
• Urine - liquid waste formed in the kidneys
• Ureter - a tube that carries urine from the kidney to the urinary bladder.
• Urethra - the tube that carries urine out of the body

 

Key Concepts

• Your cells produce four wastes; carbon dioxide, water, heat, salt, and nitrogen.
• Perspiration is liquid waste made of heat, water, and salt released through the skin.
• Kidneys filter nitrogen waste out of the blood and remove some extra water and salt from the blood.
• Urine is made of nitrogen wastes, water, and salt.
• Urine move from the kidneys to the ureters, to the urinary bladder, to the urethra, and to the outside.

 

Did you learn these Objectives?

• Are you able to explain how perspiration gets rid of wastes?
• Can you describe the function of kidneys?
• Are you able to explain how urine leaves the body?

 

 

Lesson 5 "How the Nervous System Controls the Body"

 

Key Vocabulary Terms

• Cerebellum - the part of the brain that controls balance.
• Brain stem - the part of the brain that controls automatic activities and connects the brain and the spinal cord.
• Neuron - A nerve cell
• Synapse - A tiny gap between neurons.

 

Key Concepts

• The central nervous system controls the activities of the body.
• The peripheral nervous system carries messages between the central nervous system and the other parts of the body.
• The different parts of the brain function in different ways: the cerebrum controls the way you think, learn, remember, and feel; it controls muscles that you can move by thinking about it; it interprets messages from the sense organs; the cerebellum controls balance and helps muscles work together. The brain stem controls the automatic activities of the body.
• The spinal cord is part of the central nervous system. It receives nerve messages from the brain and sends them throughout the body. Information from the body reaches the brain by way of the spinal cord.
• Impulses travel between neurons because when the impulse reaches the end of the nerve cell, a chemical is released. The chemical moves out into the synapse and touches the next neuron.
• A reflex action involves sensory neurons, association neurons, and motor neurons. Sensory neurons send a message from a sense organ to the association neurons. The association neurons send the impulse to motor neurons, which transfer the information to a muscle or gland. Messages are carried to the cell body by dendrites and from the cell body by the axon.

 

Did you learn these Objectives?

• Are you able to identify the structures and functions of the nervous system?
• Can you identify the function of the spinal cord.
• Can you describe how impulses travel?
• Are you able to explain the purpose of reflex actions?

 

 

 

Lesson 6 "The Sense Organs"

 

Key Vocabulary Terms

• Receptor cell - a cell that receives information about the environment and starts nerve impulses to send that information to the brain.
• Cornea - a clear layer of the eye that light passes through
• Iris - the part of the eye that controls the amount of light that centers.
• Pupil - the black circle in the center of the iris.
• Retina - the back part of the eye where light rays are focused
• Optic nerve - a bundle of nerves that carry impulses from the eye to the brain.
• Eardrum - a thin tissue in the middle ear that vibrates when sound waves strike it.
• Cochlea - the organ in the ear that sends impulses to the auditory nerve
• Auditory nerve - a bundle of nerves that carry impulses from the ear to the brain.

 

Key Concepts

• Light entering the eye travels through the cornea, pupil, lens, and then falls on the retina were it is turned into nerve impulses.
• Special cells on the retina send information to the optic nerve. Impulses from the optic nerve go to the brain.
• Sound waves move from the outer ear, through the ear canal, to the eardrum, to the three bones, and to the cochlea. They are changed to impulses in the cochlea.
• Skin cells are able to receive four kinds of messages: heat, cold, pressure, and pain.
• If you hold your nose while you are tasting food, it stops air from reaching the receptor cells in your nose. As a result the brain doesn't receive impulses from the nose, and you lose much of your sense of taste.

 

Did you learn these Objectives?

• Are you able to explain how the eyes "see" objects?
• Can you trace a sound wave as it travels through the ear?
• Are you able to name the four kinds of messages that receptor cells in the skin receive?
• Can you describe how the senses of taste and smell work together?

 

 

Lesson 7 "How the Endocrine System Controls the Body"

 

Key Vocabulary Terms

• Testis - the male sex organ that produces sperm cells (plural is testes)

 

Key Concepts

• The endocrine system helps to control certain body activities.
• Hormones are chemical messengers secreted by glands.
• There are many different types of hormones that affect the body in different ways, here are three examples: Aldosterone helps direct the kidney to put more sodium and water into the bloodstream. Insulin changes cells so that glucose can enter them. Growth hormone causes bones and muscles to grow.
• A feedback loop works because after hormones reach the target cells, the cells send a chemical signal back to the gland. That signal tells the gland to continue or to stop secreting the hormone.
• Responses to stress can be positive or negative; a positive response would be that stress causes more blood and glucose to go to muscles when running a race. A negative example is that a person can become ill if the stress continues for a long time.

 

Did you learn these Objectives?

• Are you able to explain what hormones do?
• Can you explain how a feedback loop works?
• Are you able to describe the stress response?

 

 

Lesson 8 "How the Body Moves"

 

Key Vocabulary Terms

• Skeletal system - the network of bones in the body.
• Red marrow - the spongy material in bones that makes blood cells.
• Osteoporosis - a disease in which bones become lighter and break easily
• Ligament - a tissue that connects bone to bone
• Tendon - a tissue that connects bone to muscle
• Voluntary muscle - A muscle that a person can control
• Involuntary muscle - a muscle that a person cannot control

 

Key Concepts

• The five functions of bone are: support the body; protect organs; allow movement; form red blood cells; and store minerals
• During a person's lifetime bone goes through several changes, it begins as cartilage and then by the time a baby is more it changes to bone, bones are built up and broken down all through life. Bones may get lighter in older people and break easily.
• Ligaments and tendons are not the same thing. ligaments connect bone to bone and tendons connect bone to muscle.
• Muscles make bones move when they contract because each end is connected to bone and it makes the bone move.
• There are three types of muscle tissue, skeletal, smooth, and cardiac.

 

Did you learn these Objectives?

• Are you able to identify five functions of bone?
• Can you explain how bones and muscles work together to produce movement?
• Are you able to describe the different kinds of muscles?

 

 

 

Chapter Summary and Review

See page 206-207

Chapter 8 Review answers are