Download Life Processes

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 lifethreatening 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