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Chapter 1

Anatomy and Physiology HAP101 Chapter Notes - Chapter 1: Supine Position, Baroreceptor, Standard Anatomical Position


Department
Anatomy and Physiology
Course Code
Anatomy and Physiology HAP101
Professor
Tania Killian
Chapter
1

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Savvy Modgil
HAP101 Chapter 1: Organization of the Human Body
LO 1.1: Define the terms anatomy and physiology
Anatomy: ana = up; -tomy = process of cutting. It is the science of body structures and relationships among them. It was first
studied by the process of dissection (the careful cutting apart of the body structures to study their relationships).
Physiology: physio = nature; -logy = study of. It is the science of body functions (i.e. how the body parts work).
The structure of a part of the body often reflects its functions, e.g. the bones of a skull join tightly to form a rigid case that
protects the brain
There are many branches of both anatomy and physiology
LO 1.2: Describe the (6) levels of organization and (11) body systems
The body has six levels of structural organization.
Level of Organization Explanation
Chemical Level Most basic level, including the atoms (the smallest units of matter that participate in chemical reactions) and molecules
(two or more atoms joined together). The most important ones are C, H, O, N, P, Ca, S. Examples include DNA and
glucose.
Cellular Level Molecules combine to form cells, the basic structural/functional units of an organism that are composed of chemicals.
Examples include muscles cells, nerve cells, and epithelial cells.
Tissue Level Group of cells and materials that work together to perform a particular function. There are four basic types of tissues:
(1) epithelial tissue, (2) connective tissue, (3) Muscular tissue, (4) nervous tissue.
Organ Level Organs are structures composed of two or more different types of tissues; they have specific functions and are
recognizable by their shape.
System Level Consists of related organs with a common function (although some organs are part or multiple systems).
Organism Level Any living individual
There are eleven body systems
Body System Function
Integumentary System Protect body; helps regulate body temperature; eliminates some wastes; helps make vitamin D; detects sensations
such as touch, pain, warmth, and cold; stores fat and provides insulation
Skeletal System Supports and protects body; provides surface area for muscle attachments; aids body movement; houses cells that
produce blood cells; stores minerals and lipids (fats)
Muscular System Participates in body movements, such as walking; maintain posture; produces heat
Nervous System Generates action potentials (nerve impulses) to regulate body activities; detects changes in body’s internal and
external environments, interprets changes, and responds by causing muscular contractions or glandular secretions
Endocrine System Regulates body activities by releasing hormones (chemical messengers transported in blood rom endocrine gland or
tissue to target organ)
Cardiovascular System Heart pumps blood through vessels, blood carries oxygen and nutrients to cells and carbon dioxide and wastes away
from cells and helps regulate acid-base balance, temp. and water content of body fluids; blood components help
defend against disease and repair damaged blood vessels
Lymphatic System and
Immunity
Returns proteins and fluid to blood; carries lipids from GI tract to blood; contains sites of maturation and
proliferation of B cells and T cells that protect against disease-causing microbes
Respiratory System Transfers oxygen from inhaled air to blood and carbon dioxide from blood to exhaled air; helps regulate acid-base
balance of body fluids; air flowing out of lungs though vocal cords produces sounds
Digestive System Achieves physical and chemical breakdown of food; absorbs nutrients; eliminates solid wastes
Urinary System Produces, stores and eliminates urine; eliminates wastes and regulates volume and chemical composition of blood;
maintains the acid-base balance of body fluids; maintains body’s mineral balance; helps regulate production of red
blood cells
Reproductive System Gonads produce gametes (sperm of oocytes) that unite to form a new organism; gonads also release hormones that
regulate reproduction and other body processes; associated organs transport and store gametes; mammary glands
produce milk
LO 1.3: Define the (6) important life processes of humans
There are six important processes of the human body
oMetabolism: is the sum of all chemical processes that occur in the body. This includes catabolism (the breakdown
of complex chemical substances into simpler components) and anabolism (the build of a complex chemical
substance from smaller, simpler components).
oResponsiveness: the body’s ability to detect and respond to change. Different cells in the body respond to
environmental changes in characteristic ways.
oMovement: motion of the whole body, individual organs, singe cells, and even tiny structures inside cells.
oGrowth: an increase in body size that is due to an increase in size of existing cells, an increase in the number of
cells, or both
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Savvy Modgil
oDifferentiation: the development of cells from an unspecialized to a specialized state. Precursor cells that can
divide and give rise to cells that undergo differentiation are known as stem cells. Each type of cell in the body has a
specialized structure or function that differs from that of its precursor.
oReproduction: the formation of new cells for tissue growth, repair or replacement (cell division); the production of
a new individual (fertilization)
LO 1.4: Identify how homeostasis functions including negative and positive feedback systems
Homeostasis: the condition o equilibrium (balance) in the body’s internal environment due to the constant interaction of the
body’s many regulatory processes. It is a dynamic condition, as the body’s equilibrium can shift in response to changing
conditions. Each structure, from cellular to the system level, contributes in keeping the internal environment balanced.
Bodily fluids: dilute, watery solutions containing dissolved chemicals that are found inside cells as well as surrounding them.
It is important to maintain the volume and composition of these fluids.
Intracellular Fluid (ICF): fluid found within cells
Extracellular Fluid (ECF): the fluid found outside body cells. The ECF fluid that fills the narrow spaces between cells of
tissues knowns is as the interstitial fluid. ECF differs depending on where it occurs in the body, e.g. ECF within blood cells
is called blood plasma.
Proper function of body cells depends on the regulation of the composition of the interstitial fluid surrounding them, i.e. it is
the body’s internal environment. Its composition changes as substances move back and forth between the fluid and blood
plasma. The exchange happens in the blood capillaries and the movement in both direction of the capillary walls provides
important material, such as glucose, oxygen, ions, etc. to tissue cells, also removing wastes from the interstitial fluid.
Homeostasis in the body is constantly being disturbed. Disruptions occur from the external environment (physical activity),
while other disruptions occur in the internal environment (what’s happening inside the body). Usually, such disruptions are
mild and homeostasis is restored quickly in the internal environment. However, in other cases, such disruptions may be
intense and prolonged (e.g. poisoning), making it harder for the body to gain equilibrium.
The body has regulatory systems that help restore equilibrium. The nervous system and the endocrine system are often
working together or independently, to provide help.
oNervous System: regulates homeostasis by sending electrical signals, i.e. nerve impulses (action potentials) to
organs that counteract changes from the balanced state
oEndocrine System: includes many glands that secrete messenger molecules called hormones into the blood.
oNerve impulses cause rapid change, but hormones work slowly. Both means of regulation provide homeostasis
through negative feedback systems
Feedback systems: a cycle of events in which the status of a body condition is monitored, evaluated, changed, re-monitored,
revaluated, and so on. A controlled condition is any monitored variable (e.g. blood temperature, blood pressure). A stimulus
is any disruption that causes a change in the controlled condition. A feedback loop contains three components: a receptor, a
control centre, and an effector.
oReceptor: body structure that monitors changes in a controlled condition and sends input to a control centre. This is
called the afferent pathway, since the information flows towards the control centre. The input occurs in the form of a
nerve impulse or chemical signals, e.g. the skin has nerve endings that detect a change in the external environment,
such as temperature change.
oControl Centre: the brain sets a range of values within which a controlled condition should be maintained. The
brain evaluates the input it receives from the receptors, generating output commands when needed. Output from the
control centre occurs as nerve impulses, hormones or other chemical signals. This is called the efferent pathway
because the information is flowing away from the control centre.
oEffector: a body structure that receives output from the control centre and produces a response or effect that
changes the controlled condition.
oEXAMPLE: when your body temperature drops sharply, the skin (receptors) relays this information to the brain
(control centre). The brain sends nerve impulses (output) to your skeletal muscles (effectors). The result is shivering,
causing goosebumps and your skin hair to rise. When the hair rises, it generates heat, raising your body temperature.
There are two feedback systems:
oNegative Feedback Systems: type of feedback system that reveres a change in a controlled condition. For
example, some internal or external stimulus is causing BP (the controlled condition) to rise. Pressure-sensitive nerve
cells, known as baroreceptors (the receptors), located in the walls of blood vessels detect this rise in BP. The
baroreceptors send nerve impulses (the input) to the brain (the control centre), which interprets the impulses and
responds by sending nerve impulses (the output) to the heart/blood vessels (the effectors). The heart rate decreases,
causing blood vessels to dilate (widen), causing the overall BP to decrease, bring the body back to homeostasis.
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