Homeostasis and Body Systems

Human Body Organization

Is composed of

Organ Systems

are composed of

Organs

are composed of

Tissues

are composed of

Cells

The Human Body

Nervous System

Major Structures• brain, spinal cord, nerves,

sense organs

Functions• regulates behavior;

maintains homeostasis; regulates other organ systems; controls sensory and motor functions

•Sensory (or afferent) neurons: send information from sensory receptors (e.g., in skin, eyes, nose, tongue, ears) TOWARD central nervous system.

•Motor (or efferent) neurons: send information AWAY from central nervous system to muscles or glands.

•Interneurons: send information between sensory neurons and motor neurons. Most interneurons are located in the central nervous system.

Nerve Cells

Endocrine SystemMajor Structures• hypothalamus, pituitary, pineal,

pancreas, thyroid, parathyroid, adrenal, testes, and ovaries

Functions• regulates body temperature,

metabolism, development, and reproduction; maintains homeostasis; regulates other organ systems

Interactions with other systems• Nervous system and

circulatory system

Circulatory SystemMajor Structures• heart, blood vessels, blood,

lymph nodes and vessels, lymph , blood cells

Functions• transports nutrients, wastes,

hormones, and gases

Interactions with other systems• Nervous system :

– The brain regulates heart rate and blood pressure.

• Excretory– Cleans the blood

• Respiratory system– Gas exchange in the lungs

• Carbon dioxide and Oxygen

Cells of the Circulatory System• Red Blood Cells carry

oxygen and carbon dioxide. • White Blood Cells attack

and destroy germs in the body.

• Platelets are bits of a blood cell that help stop bleeding.

• Plasma is the liquid part of the blood. It includes salts, waste, nutrients, water,

CO2 & O2

Excretory SystemMajor Structures• kidneys, urinary bladder,

ureters, urethra, skin, lungs; Nephron- filtration unit of kidney

Functions• removes wastes from

blood; regulates concentration of body fluids

Interactions• Circulatory system• Endocrine system

Respiratory System

Major Structures• Nose, mouth, voice box

(larynx), trachea, bronchi, lungs, alveoli (air sacs)

Functions• moves air into and out of

lungs; controls gas exchange between blood and lungs

Interactions:• Circulatory system• Nervous system

Pathway: nose->pharynx->larynx-> trachea->bronchi-> Lungs-> bronchioles->alveoli

Muscular SystemMajor Structures• skeletal, smooth, and cardiac muscle

tissues

Functions• moves limbs and trunk; moves

substances through body; provides structure and support

Interactions with other systems• Skeletal system - provide skeletal

movement

• Digestive system- controls entrances and exits of digestive tract

• Endocrine system- shiver to produce heat

• Nervous system – helps sense of balance, pressure

• Respiratory system- makes diaphragm contract & relax

• Cardiovascular system – heart pumps to provide circulation

Types of Muscle Cells

Cardiac Muscle cells - are branched and striped

Skeletal Muscle cells - are striped and have many nuclei

Smooth muscles- are pointed at both ends

Skeletal SystemMajor Structures• Bones, joints and Bone marrow

Functions• protects and supports body and

organs; interacts with skeletal muscles; produces red blood cells, white blood cells, and platelets

Interactions with other systems• Nervous System

– Bones provide calcium needed for proper functioning of nerve cells

• Circulatory system– Skeletal system protects

internal organs and produces blood cells.

Cells of the Skeletal System

Cells in the Bone that work with the Circulatory System

Integumentary SystemMajor Structures• skin, nails, hair, fat, nerves and blood

vessels

Functions• protects against injury, infection,

production of Vitamin D, and fluid loss; helps regulate body temperature

• Interactions with other systems– Immune system

• First line of defense against infection

– Nervous system• Complex network of nerves

in skin send and receive impulses to and from brain, creating sense of touch.

• Sense heat, cold, pain, pressure & touch

• Melanocyte- makes pigment (melanin)

• Langerhans' cell- frontline defense for the immune system in skin

• Adipose (fat) cells- provide insulation from heat and cold

Cells of the Integumentary

Digestive SystemMajor Structures• mouth, throat, esophagus,

stomach, liver, pancreas, small and large intestines

Functions• extracts and absorbs nutrients

from food; removes wastes; maintains water and chemical balances

Interactions with other systems• Integumentary system

– vitamin D activated in skin helps the absorption of calcium from digestive tract.

• Reproduction system, – Adequate nutrients, including

fats, are essential for conception and normal development.

Sequence of food pathway through system•Mouth, esophagus, stomach, small intestine and large intestine.

Digestive SystemWhat Benefits Do Gut Bacteria Provide?

• Bacteria produce enzymes that digest polysaccharides in plant cell walls. Plants contribute to fiber in our diet for a healthy colon, but the enzymes released by good bacteria let us get the most nutrition from vegetables

• Some digestive system bacteria make vitamin K and B group vitamins – (difficult to get from food) Humans can’t make these. Bacteria help maintain an optimum pH and stimulate the immune system. Gut bacteria breakdown drugs, hormones and cancer-causing environmental substances

• Bacteria in the human gut are beneficial to their host, and enjoy a safe environment .

• What type of symbiotic relationship is this an example of ?

MUTUALISM

Immune SystemMajor Structures• white blood cells, lymph

nodes and vessels, skin, spleen

Functions• defends against pathogens

and diseases

Interactions• Circulatory- delivers

WBC’s where needed• Skeletal- makes WBC’s in

red bone marrow

Cells of the immune system

What happens:

1.B cells recognize pathogens by the proteins (antigens) on their surface.

2.Helper T cells activate the B cells.

3.B cells divide to make plasma and memory B cells.

4.Plasma B cells produce antibodies that attach to the pathogen marking it for destruction.

5.Macrophages see the antibodies and eat pathogen cells

6.Memory cells are stored in the lymph nodes. They give a rapid immune response the next time the pathogen attacks.

Reproductive System

Major Structures• ovaries, fallopian tubes,

uterus, and breasts (in females); testes and penis (in males)

Functions• The male and female gonads (testes

and ovaries) produce sex cells (ova and sperm) and the hormones necessary for the proper development, maintenance, and production of gametes and offspring

EggSperm

Gametes of the Reproduction system