Human Body Systems

Key Ideas of Homeostasis• How do the skeletal and muscular systems

help the body maintain homeostasis?• How does the integumentary system help

the body to maintain homeostasis?• How do the nervous and endocrine systems

help the body to maintain homeostasis?• How do the digestive and excretory systems

help the body maintain homeostasis?• How do the circulatory and respiratory

systems help the body to maintain homeostasis?

Skeletal/Muscular Systems• These systems enable

movement and provide support and protection for tissues and organs.

• Skeletal system has 5 main functions:– Support (give body shape

and structure)– Protection (protect internal

organs)– Movement (joints allow for

motion)– Mineral storage (calcium,

phosphorus)– Blood cell production

(marrow)

How do Muscles Cause Bones to Move?

• Muscles are attached to bones by tendons.

• Tendons are strips of very strong, flexible connective tissue.

• Pairs of muscles cause bones to move- one pair pulls and one pair pulls the other way (when one contracts the other relaxes).

Three Main Kinds of Muscle Tissue

• Skeletal- are voluntary, you can control them. They help move the body.

• Smooth- involuntary, you cannot control them, found in blood vessels, digestive system, bladder.

• Cardiac- involuntary, found in heart, you cannot control.

Integumentary System

• Functions of the skin:– Protection– Disease prevention– Temperature control– Waterproofing

Nervous System

• Consists of two main parts:– Central

nervous system- Brain and spinal cord.

– Peripheral Nervous system- axillary nerves (arms, legs).

The NeuronNerve cells are the largest in the body.

Types of Neurons

• Motor- transmit messages from the CNS to muscles and other organs.

• Sensory- transmit messages from the sensory organs to the CNS.

Endocrine SystemHas five main

functions:– Regulate

metabolism.– Maintain salt,

water, and nutrient balance in the blood.

– Control responses to stress.

– Regulate growth, development, reproduction.

– Produce hormones.

Digestive System• The process

of breaking down foods into molecules that the body can use.

• Uses both chemical and mechanical means.

Excretory System• The removal of

metabolic wastes.• Metabolic wastes

include: water, salts, CO2, nitrogenous wastes.

• Main organs are: Kidneys, Ureters, and Bladder, and Lungs.

Respiratory System• The Respiratory

System brings Oxygen into the body and and carries Carbon Dioxide out of the body.

• The Lungs are the main organs of the Respiratory System.

Cardiovascular SystemWhat Is the

Cardiovascular System?The heart, blood vessels, and blood make up the cardiovascular system.The cardiovascular system carries nutrients, oxygen, hormones, and wastes through the body and distributes heat to maintain homeostasis.

Parts of the Circulatory System• Arteries- carry blood away from the heart.• Veins- carry blood to the heart.• Capillaries- exchanges gases and nutrients from

vessels to cells.

The Immune System• Disease is caused by a disruption in a human

body system that leads to a corresponding disruption in homeostasis.

• Disease falls into two categories:– Infectious, can be transmitted from one organism to

another. Infectious diseases are caused by pathogens.

– Non-infectious, cannot be transmitted from one organism to another.

• Pathogens can spread disease by air, contact with contaminated objects, ingesting contaminated food, by contact with a vector.

• A vector is an intermediate organism that transfers a pathogen from one organism to another.

We can avoid disease by practicing:– Good hygiene– Living a healthy lifestyle– Eating completely cooked meat– Getting enough sleep– Exercising– Eating a balanced diet– Drinking plenty of water

How does the Immune System Work?

Key Concept: The Immune System consists of Organs, Cells, and Molecules that fight infection.

• Your body has organs, cells, and tissues that protect you from pathogens.

• The body system that fights off infection is the Immune System.

ImmunityBodily Defenses:• Skin- is the bodies 1st line of defense.• Skin prevents pathogens from entering the

body.• Oil/sweat make it difficult for pathogens to

survive on the skin’s surface.• Pathogens enter the body through openings

in the skin (cuts, scrapes), eyes, nose , mouth, and ears.

• Tears, mucous, and tiny hairs help to trap and remove pathogens.