CIRCULATION

Once food has been digested, it must be transported to the cells for them to use.This is the function of the circulatory system.

CIRCULATORY SYSTEM…..

INCLUDES THE HEART, BLOOD VESSELS, AND BLOOD.

The circulatory system also…..

transports oxygen to the cells from the lungs.

WASTES……..

produced by the cells are transported out of the cells to be processed by other parts of the body.

Carbon dioxide produced by respiration is transported to the lungs to be excreted.Nitrogen-containing wastes from metabolism of digested food are sent to liver and kidneys to be excreted.

Blood vessels also carry…

Chemical messengers-also known as hormones andThe products that give the body immunity-antibodies.

TRANSPORT

Transport into and out of cells happens by diffusion.

HOMEOSTASIS

The circulatory system maintains homeostasis byTransporting nutrients around the bodyPicking up wastes to be excretedRegulating body temperature Sending messages to organs that maintain blood sugar levels and amount of water in blood. Carrying products that fight infection.

BLOOD

Made of mostly plasma, which is mostly water,And red blood cells for carrying oxygen,And white blood cells for fighting infection, (more later)And platelets to aid in clotting.

DISORDERS

HEART ATTACK-parts of the heart muscle dieSTROKE(cerebral hemorrhage)-parts of the brain are damagedSaturated fats (raises cholesterol levels), high blood pressure are implicated in heart disease

REPAIR

Rest, medication, surgery (coronary bypass, angioplasty) to stop and repair damagePhysical therapy

PREVENTION

Diets high in fiber (fruits, veggies, whole wheat), low in saturated fat (skim milk, fish)Exercise

Sometimes medication is used to lower blood pressure or cholesterol levels

HOMEOSTASIS/Immunity

A multicellular organism can maintain homeostasis easier by delegating different functions to different organ systems

All organisms must maintain homeostasis to continue to surviveEnzymes, to regulate the rate of reactions, and-Hormones, to transport chemical messages throughout an organism, are a few things that help maintain homeostasis

DISEASE

Disease is considered a FAILURE OF HOMEOSTASISDisease may be caused by a disease-causing organism, called a pathogen (virus or bacteria, for ex.)Disease may also be caused by disruption in internal processes-

as in Cancer, a failure of the enzymes that control mitosis or-Some diseases are caused by failure of an organ to do its job, such as in diabetes, where the pancreas does not produce enough insulin.

Lines of Defense/ Immunity

To resist disease, the human body has a barrier of skinOpenings, such as noses, contain structures to prevent invasionAnything inside is first caught and rejected, or killed by stomach acids

Blood/Immunity

The final line of defense is in the blood-white blood cells that can engulf invaders or recycle used cells or destroy “mistakes” and-Production of antibodies that fight foreign substances

Lymph System

In addition to circulation of blood through vessels, pumped by the heart, humans have circulation of lymph .Lymph is similar in chemical composition to plasma (no cells) and surrounds all cells in the bodyThis system also has vessels as well as glands, but no pump

Fluid moves slowly through here, allowing white blood cells and antibodies to work on foreign invaders

Types of Immunity

Active Immunity occurs when the body makes its own antibodiesThis will occur from contracting the disease and recovering; ORBy receiving a vaccine, which contains dead or weakened virusesThis immunity may last a lifetime

Passive Immunity-

Can produce temporary immunity by injecting antibodies into the body after one is exposed to a disease

DISORDERS-Include AIDS, caused by HIV, which damages the immune system, leaving the body unable to defend itself from infections

Control of Homeostasis

FEEDBACK maintains a constant state in the bodySystems work together to monitor any changes and adjust to correct themBody temperature is maintained by communication between the brain, nervous system, and sweat glands.

Negative Feedback

Cells in the thyroid and in the pituitary constantly monitor levels of the hormones using receptors on their plasma membranes

Increase in one thing decreases the otherFor example, thyroid stimulating hormone (TSH) is produced by the pituitaryThyroid hormone is produced by the thyroidWhen the thyroid hormone is high enough, as determined by the pituitary, TSH is no longer produced, slowing production of thyroid hormoneLow thyroid hormone causes TSH to be produced