Biology 1-2. Physiology Physiology-the study of the functions of an organism. The cell is the basic...

Introduction to PhysiologyBiology 1-2

PhysiologyPhysiology-the study of the functions of an organism.The cell is the basic unit of all living organisms.

All organisms are made of one or more cells.

TissuesIn multicellular organisms, cells have specialized roles

and form tissues.Tissue-a group of cells with a common structure and

function. Epithelial-tightly packed sheets of cells; line surfaces. Connective-loosely packed cells; bind and support other tissues. Muscle-movement Nervous-forms a communication network.

OrgansDifferent tissues

combine to form organs.Organ-a structure

composed of two or more tissues to carry out a particular function.

A group of organs that work together to carry a series of related tasks is called an organ system.

Organ SystemsThere are 11 organ systems in the human body.

Digestive-breakdown of food molecules that enter the body.

Immune-defense against diseases.Circulatory-moves blood through the body.Respiratory-gas exchange.Nervous-regulation of other systems.Reproductive-production of gametes for the production of

offspring.

Organ Systems cont’dIntegumentary-protection and temperature regulation.

Epidermis-epithelial cells, prevents entry/water loss. Top layers are dead, layers underneath replace lost cells.

Dermis-connective tissue and glands. Sweat/hair/oil glands, blood vessels and sensory receptors are

found here.

Organ Systems cont’dMuscular-movement of the skeleton.

Skeletal muscles work in pairs.Tendons (connective tissue) holds muscle to bone.

Organ Systems cont’dUrinary-regulation of blood volume and content;

removes wastes and recycles water.Blood enters the kidneys and water and other materials are

forced out of the blood.Kidney returns most water and ions to the blood.

Wastes are concentrated (urine) and sent to bladder. Bladder stores urine until it is removed.

Organ Systems cont’dSkeletal-movement, support, protection.

Bones store calcium.Ligaments (connective tissue) holds bones together.Cartilage-connective tissue, padding between joints and

flexible structures of the nose and ears.Joint-where two bones meet.

Organ Systems cont’dEndocrine Secretion of regulatory hormones; long term

development and growth.Hormone-chemical signal that triggers a change in activity

of a cell.Nervous system or the hypothalamus (in the brain) trigger

the release of hormones from other glands. Pituitary, thyroid and adrenal glands. Hormones bind to target organs and cause them to respond.

HomeostasisThe 11 organ systems work together to provide the body

with oxygen and nutrients and remove wastes (homeostasis).Homeostasis-the maintenance of a constant internal

environment. Negative feedback is the primary mechanism of homeostasis.

When there is too much of something, the body works to reduce it.

When there is not enough, the body works to increase the amount.