Introduction to Anatomy & Physiology Anatomy - is the science of structure and the relationship among structures. Physiology – is the science of body functions….how the body parts work Levels of Organization – chemical, cells, tissues, organs, organ systems, and organism 4 Tissue types – epithelial, connective, muscular, nervous

Life Processes Metabolism – the sum of all the chemical processes that occur in the body. Responsiveness – the body’s ability to detect and respond the changes in its internal or external environment Movement – motion of the whole body (from chemicals to the entire organism) Growth – is an increase in body size Differentiation – unspecialized cells become specialized cells (ex. From an egg cell to a human) Reproduction – cell growth, cell replacement, creating a new individual

Homeostasis The maintenance of relatively stable conditions. It ensures that the body’s internal environment remains steady despite changes inside and outside the body. Each body system contributes to homeostasis in some way!!!! We will use the term homeostasis over and over again during this year! We will examine how each system works with other systems to maintain homeostasis!

Feedback systems A feedback system is a cycle of events in which a condition in the body is continually monitored, evaluated, changed, remonitored, reevaluated, and so on. Any disruption that causes a change in a controlled condition is called a stimulus.

3 Components of a Feedback system 1.Receptor – body structure that monitors changes in a controlled condition and sends info called Input to a control center. Input is in the form of a nerve impulse or chemical signal. Ex – nerve endings in the skin that sense temperature 2.Control Center – Ex – the brain, sets the range of values within a controlled condition that should be maintained, evaluates the input it receives from the receptors, and generates output commands. Output is information, in the form of nerve imputes or chemical signal that is relayed to an effector.

3 Components of a Feedback system 3. Effector – receives output from the control center and produces a response that changes the controlled condition. Nearly every organ or tissue in the body can behave as an effector. Ex – your body temp drops, your brain (control center) sends nerve impulses to your skeletal muscles (effectors) that cause you to shiver, which generates heat and raises your temperature (to maintain homeostasis).

Negative Feedback System It reverses a change in a controlled condition. Example – Blood pressure A stimulus causes bp to rise Cells (baroreceptors) located in the walls of blood vessels (the receptors) detect a rise in pressure The baroreceptors send nerve impulses (input) to the brain (the control center) The brain interprets the impulses and responds by sending nerve impulses (output) to the heart (the effector) The heart rate decreases causing the blood pressure to decrease (response).

Negative Feedback System Regulate conditions in the body that are held fairly stable over long periods of time Examples : blood pressure, blood glucose and body temperature.

Positive Feedback System Strengthens a change in a controlled condition. Conditions don’t happen very often…such as child birth, ovulation and blood clotting. It must be shut off If not stopped….it can “run away” and produce life- threatening changes in the body.

Homeostasis and disease When homeostasis is maintained…body is healthy! When there are imbalances…a disorder, disease may occur. If it’s severe death may occur. Disorder – any abnormality of structure and/or function Disease – illness with recognizable symptoms and signs Symptom – are subjective, not apparent to observer (headache, nausea) Sign – can be observed and measured (bleeding, vomiting, fever, rash)

Aging and homeostasis Normal process where there is a progressive decline in the body’s ability to restore homeostasis Examples: wrinkled skin, gray hair, loss of bone mass, decreased hormones, decreased kidney function, menopause, etc.

Anatomical terms Anatomical position – the subject stands erect facing the observer, with the head level and the eyes facing forward. The feet are flat on the floor and directed forward, and the arms are at the sides wit the palms turned forward.

Body Regions Head – skull and face Neck – supports the head and attaches it to the trunk Trunk – chest, abdomen, and pelvis Upper limbs – shoulder, arm pit and arm, forearm, wrist and hand Lower limbs – buttock, thigh, leg, ankle and foot

Directional terms See page 12