Chapter 8: Body Structure and Function

artery

A blood vessel that carries blood away from the heart

capillary

A tiny blood vessel; food, oxygen, and other substances pass from the capillaries into the cells

cell

The basic unit of body structure

digestion

The process of physically and chemically breaking down food so it can be absorbed for use by the cells

hemoglobin

The substance in red blood cells that carries oxygen and gives blood its color

hormone

A chemical substance secreted by the endocrine glands into the bloodstream

immunity

Protection against a disease or condition; the person will not get or be affected by the disease

menstruation

The process in which the lining of the uterus breaks up and is discharged from the body through the vagina

metabolism

The burning of food for heat and energy by the cells

organ

Groups of tissues with the same function

peristalsis

involuntary muscle contractions in the digestive system that move food down the esophagus through the alimentary canal

respiration

The process of supplying the cells with oygen and removing carbon dioxide from them

system

Organs that work together to perform special functions

tissue

A group of cells with simliar functions

vein

A blood vessel that returns blood to the heart

GI

Gastrointestinal

RBC

Red blood cell

WBC

White blood cell

What do cells need to live and function?

Cells need food, water, and oxygen to live and function

Name the structures of of a cell?

1.) Cell membrane (is the outer covering. It encloses the cell and helps it hold its shape.)

2.) Cytoplasm (surrounds the nucleus. Cytoplasm contains smaller structures that perform cell functions.)

3.) Nucleus (is the control center of the cell. It directs the cell's activities. It is the center of the cell. It also controls cell reproduction.)

What are the smaller structures contained inside of the cytoplasm of a cell?

It contains smaller structures that perform cell functions such as:

- Protoplasm (semiliquid substance much like an egg white)

- Chromosomes (threadlike structures in the nucleus. There are 46 chromosomes that contain genes.)

- Genes (control the traits children inherit from their parents. Height, eye color, and skin color)

How many chromosomes are there in a cell?

46 chromosomes

How does a cell reproduce?

Cells reproduce by dividing in half. The process of cell division is called mitosis

1.) the 46 chromosomes arrange themselves in 23 pairs

2.) as the cell divides, the 23 pairs are pulled in half

3.) The two new cells are identical. Each has 46 chromosomes.

What are the different types of tissues?

- Epithelial tissue (covers internal and external body surfaces. Tissue ling the nose, mouth, respiratory tract, stomach, and intestines. So are the skin, hair, nails, and glands.)

- Connective tissue (anchors, connects and supports other tissues. Bones, tendons, ligaments, and cartilage.

Blood is a form of connective tissue.)

- Muscle tissue (stretches and contracts to let the body move.)

- Nerve tissue (receives and carries impulses to the brain and back to body parts.)

How are organs formed?

Groups of tissue with the same function

Do organs have only one function or more than one function?

more than one function

What is the organization of the body?

cells, tissues, organs, systems

Integumentary system

skin

What are the different layers of the skin?

- epidermis (outer layer)

- dermis (inner layer)

Integument

covering

Which body system is the largest?

Integumentary system

pigment

gives skin its color

Which layer of the skin makes up blood vessels, nerves, sweat glands, and oil glands or hair roots?

The dermis

subcutaneous tissue

thick layer of fat and connective tissue that supports the epidermis and the dermis.

How does hair help the body?

protects organs such as the nose, ears, and eyes from dust, insects and other foreign objects.

How does nails help the body?

protect the tips of the fingers and toes. They help fingers pick up and handle small objects.

How does sweat glands help the body?

help the body regulate temperature.

What is sweat made of?

water, salt, and small amount of wastes.

How does oil glands help the body?

helps keep the hair and skin soft and shiny.

What are different function that the skin provides?

- It is the body's protective covering

- It prevents microogansms and other substances from entering the body

- It prevents excess amounts of water from leaving the body

- It protects organs from injury

- Nerve endings n the skin sense both pleasant and unpleasant stimulation. Nerve endings are over the entire body. They sense cold, pain, touch, and pressure to protect the body from injury

- It helps regulate body temperature. Blood vessels dilate (widen) when the temperature outside the body is high. More blood is brought to the body surface for cooling during evaporation. When blood vessels constrict (narrow), the body retains heat, because less blood reaches the skin.

Musculoskeletal system

provides the framework for the body. It lets the body move. It also protects and gives the body shape.

How many bones does the human body have?

206 bones

What are the four types of bones?

1.) Long bones (bear the body's weight. Leg bones.)

2.) Short bones (allow skill and ease in movement. Bones in the wrist, fingers, ankles, and toes.)

3.) Flat bones (protect the organs. Ribs, skull, pelvic bones, and shoulder blades.)

4.) Irregular bones (vertebrae in the spinal column. Allows various degrees of movement and flexibility.)

Periosteum

the membrane that surrounds bone. It contains blood vessels that supply bone cells with oxygen and food.

Bone marrow

A soft tissue inside the bone that produces blood cells

joints

is the point at which two or more bones meet.

cartlige

connective tissue at the end of the long bones. It cushions the joint so that the bone ends do not rub together.

synovial membrane

lines the joints. It secrets synovial fluid. The fluid acts as a lubricant so the joint can move smoothly.

ligaments

Bones are held together at the joint by strong bands of connective tissue

What are the three types of joints?

1.) Ball-and-socket joint (allows movement in all directions. Hips and shoulders)

2.) Hinge joint (allows movement in one direction. The elbow.)

3.) Pivot joint (allows turning from side to side. Connects the skull to the spine.)

How many muscles are in the human body?

500 muscles

What are the different types of muscles?

- Voluntary muscles/skeletal muscles (Can be controlled consciously. Muscles attached to bones.)

- Involuntary muscles/smooth muscles (work automatically. You cannot control them. Stomach, intestines, blood vessels, and other body organs.)

- Cardiac muscle (is in the heart. It cannot be controlled.)

What are the three functions of muscles?

1.) Movement of body parts

2.) Maintenance of posture

3.) Production of body heat

striated

striped or streaked (muscles)

tendons

Connect muscle to bone

What happens when muscles contract when you move?

they burn food for energy and heat is produced

Nervous system

The nervous system controls, directs, and coordinates body functions.

What are the two main divisions of the nervous system?

- central nervous system (CNS): consists of the brain and spinal cord.

- peripheral nervous system (it involves the nerves throughout the body.)

How many pairs of cranial nerves and spinal nerves does the peripheral nervous system have?

the peripheral nervous system has 12 pairs of cranial nerves and 31 pairs of spinal nerves.

What is the automatic nervous system divided into?

divided into the sympathetic nervous system and the parasympathetic nervous system.

myelin sheath

a protective covering of the nerve fibers. They conduct impulses faster than those fibers without it.

What are the three main parts of the brain?

- The cerebrum

- The cerebellum

- The brainstem

Cerebrum

- The largest part of the brain

- The center of thought and intelligence

- Divided into two halves called the right and left hemispheres. The right hemisphere controls movement and activities on the body's left side. The left hemisphere controls the right side.

Cerebral cortex

- The outside of the cerebrum

- Controls the highest brain functions (reasoning, memory, consciousness, speech, voluntary muscle movement, vision, hearing, sensation, and other activities.)

Cerebellum

- Regulates and coordinates body movements

- Controls balance and the smooth movements of voluntary muscles

Brainstem

- Connects the cerebrum to the spinal cord

- Contains the midbrain, pons, and medulla.

What does the medulla control?

controls heart rate, breathing, blood vessel size, swallowing, coughing and vomiting.

How long is the spinal cord?

17-18 inches long

What are three layers of connective tissue (meninges)?

- dura mater (The outer layer lies next to the skull. It is a tough covering.)

- arachnoid (The middle layer.)

- pia mater (The inner layer.)

arachnoid space

The space between the middle layer (arachnoid) and the inner layer (pia mater). This space is filled with cerebrospinal fluid.

cerebrospinal fluid

it is fluid in the arachnoid space. It circulates around the brain and spinal cord protects the central nervous system. It cushions shock that could easily injure the brain and spinal cord structures.

Periphreal Nervous System (PNS)

- Contains 12 pairs of cranial nerves and 31 pairs of spinal nerves

- Cranial nerves conduct impulses between the brain and the head, neck, chest, and abdomen.

- Spinal nerves carry impulses from the skin, extremities, and the internal structures not supplied by cranial nerves.

- Some peripheral nerves form the autonomic nervous system.

Automatic Nervous System (ANS)

- Controls involuntary muscles and certain body functions that occur automatically.

- Divided into the sympathetic nervous system and the parasympathetic nervous system.

- The sympathetic nervous system speeds up functions.

- The parasympathetic nervous system slows functions.

What are the five sense?

sight, hearing, taste, smell, and touch.

What are the three layers of the eye?

- The sclera, the white of the eye, is the outer layer.

- The choroid is the second layer. (Blood vessels, the ciliary muscle, and the iris make up the choroid.)

- The retina is the inner layer. (It has receptors for vision and the nerve fibers of the optic nerve._

What happens when light enters the eye?

The pupil constricts (narrows) in bright light

What happens to the eye when you are in dim or dark places?

The pupil dilates (widens) in dim or dark places

How is light carried to the brain?

by the optic nerve.

aqueous chamber

seperates the cornea from the lens. The chamber is filled with a fluid called aqueous humor.

aqueous humor

fluid that helps the cornea keep its shape and position.

vitreous humor

is behind the lens. It is a gelatin-like substance that supports the retina and maintains the eye's shape.

What are the three parts of the ear?

- External ear (pinna or auricle. Sound waves guided into the auditory canal)

- Middle ear (contains the eustachian tube)

- Inner ear (contains the semicircular canals and the cochlea)

What is the pathway of light through the eye?

light through the eye to the cornea -

aqueous humor - through pupil -

lens - vitreous humor - retina -

optic nerve - brain - the occipital lobe

What gives the eye its color?

iris

auditory canal

the area that sound waves pass through to reach the eardrum

cerumen

a waxy substance secreted from glands in the auditory canal (ear wax).

tympanic membrane

eardrum

eustachian tube

connects the middle ear and throat.

What are the three ossicles?

- malleus (it looks like a hammer)

- incus (it looks like an anvil)

- stapes (it looks like a stirrup)

What is the pathway of sound through the ear?

First the Sound waves are guided into the external ear (pinna or auricle) to the auditory canal.

Second the sound waves travel to the eardrum (tympanic membrane).

Third it enters the middle ear that contains the eustachian tube and three small bones called ossicles. Air enters the eustachian tube so that there is equal pressure on both sides of the eardrum. The ossicles amplify sound received from the eardrum and transmit the sound to the inner ear.

Fourth, the fluid inside the cohlea carries sound waves from the middle ear to the acoustic nerve.

Fifth, The acousitic nerve then carries the message to the brain.

cochlea

looks like a snail shell. It contains fluid. The fluid carries sound waves from the middle ear to the acoustic nerve.

circulatory system

The circulatory system is made up of the blood, heart, and blood vessels.

What are the different functions of the circulatory system?

- Blood carries food, oxygen, and other substances to the cells.

- Blood removes waste products from cells.

- Blood and blood vessels help regulate body temperature.

- The system produces and carries cells that defend the body from microbes that cause disease.

blood

The blood consists of blood cells and plasma.

Red blood cells (RBCs)

are called erythrocytes filled with oxygen.

White bood cells (WBCs)

are called leukocytes that protect the body from infection.

Platelets

are called thrombocytes and they are needed for blood clotting.

Where are red blood cells destroyed?

destroyed by the liver and spleen as they wear out.

Where are red and white blood cells produced?

bone marrow

How many red blood cells are there in the body?

25 trillion