chapter 1 An Introduction to the Human Body Flashcards
Anatomy
is the
science of body structures and the relationships among them.
physiology
is the
science of body functions—how the body parts work.
six levels of organization
chemical, cellular, tissue, organ, system,
and organismal levels of the organization
Chemical level
-the very basic level
-includes the atom which is the smallest unit of matter that participate in chemical reactions,
Cellular level
Molecules combine to form cells, the basic
structural and functional units of an organism that are composed
of chemicals.
Tissue level
groups of cells and the materials
surrounding them that work together to perform a particular
function,
4 types - epithelial
connective
muscular
nervous
organ level
different types of tissues are
joined together.
structures that are composed of two
or more different types of tissues;
they have specific functions
and usually have recognizable shapes.
system level
consists of related organs (paragraphs) with a
common function.
organismal level
Different types of tissue joined together
All the parts of the human body functioning together constitute the total
organism. (a living individual)
anabolism
the building up of complex chemical substances
from smaller, simpler components.
(to build)
metabolism
is the sum of all chemical processes
that occur in the body (2 phases)
1) catabolism
2) anabolism
catabolism
breakdown of complex chemical substances into simpler components.
nerve impulses
electrical signal (action potentials)
6 basic life processes
Metabolism
Responsiveness
movement
growth
differentiation
reproduction
When any one of the life processes ceases to occur properly, the
result is death of cells and tissues, which may lead to death of the organism
growth
increase in body size that results from an increase
in the size of existing cells, an increase in the number of cells, or
both.
differentiation
is the development of a cell
from an unspecialized to a specialized state.
- Such precursor ( ancestor) cells,
which can divide and give rise to cells that undergo differentiation,
are known as stem cells. - through differentiation,
a single fertilized human egg (ovum) develops into an
embryo, and then into a fetus, an infant, a child, and finally an adult.
Reproduction
(1) the formation of
new cells for tissue growth, repair, or replacement,
(2) the production of a new individual.
Homeostasis
is the maintenance of relatively stable conditions in
the body’s internal environment
ex maintaining body fluid
EX (the level of glucose in
blood normally stays between 70 and 110 milligrams of glucose per
100 milliliters of blood).
Most often, the nervous system and the endocrine system, working together or independently, provide the needed corrective measures.
intracellular fluid (ICF)
fluid inside cell
extra-cellular fluid (ECF)
fluid outside the cell (differs depending on where it occurs in the body)
ECF within blood vessels is termed blood
plasma, within lymphatic vessels, is called lymph, in and around the
brain and spinal cord it is known as cerebrospinal fluid, in joints it is
referred to as synovial fluid, and the ECF of the eyes is called
aqueous humor and vitreous body
extra- = outside
interstitial fluid
The ECF
that fills the narrow spaces between cells of tissues is known as
exchanged between the external environment, internal environment, and body cells in order to maintain homeostasis
oxygen and nutrients enter the plasma. these substances are transported throughout the body by the cardiovascular system. Oxygen and nutrients eventually leave plasma by crossing the walls of blood capillaries and entering interstitial fluid
Blood capillaries are specialized to
allow the transfer of material between plasma and interstitial fluid.
From interstitial fluid, oxygen, and nutrients are then taken up by cells and metabolized for energy
During this process, the cells produce waste
products, which enter again the interstitial fluid and then move across the blood capillary walls into plasma
The cardiovascular system transports these
wastes to the appropriate organs for elimination from the body into the
external environment.
nitrogen-containing wastes- urea and ammonia (eliminated by the urinary system)
exchanged between the external environment, internal environment, and body cells in order to maintain homeostasis
oxygen and nutrients enter the plasma. these substances are transported throughout the body by the cardiovascular system. Oxygen and nutrients eventually leave plasma by crossing the walls of blood capillaries and entering interstitial fluid
Blood capillaries are specialized to
allow the transfer of material between plasma and interstitial fluid.
From interstitial fluid, oxygen, and nutrients are then taken up by cells and metabolized for energy
During this process, the cells produce waste
products, which enter again the interstitial fluid and then move across the blood capillary walls into plasma
The cardiovascular system transports these
wastes to the appropriate organs for elimination from the body into the
external environment.
nitrogen-containing wastes- urea, and ammonia (eliminated by the urinary system)
endocrine system
glands that secrete messenger molecules called hormones into the
blood.
feedback system or feedback loop (3)
is a cycle of events in which the status of a body
condition is monitored, evaluated, changed, remonitored, reevaluated,
and so on
1) receptor
2) control center
3) effector
A group of receptors and effectors communicating with their
control center forms a feedback system that can regulate a controlled
condition in the body’s internal environment
negative feedback
positive feedback
controlled condition (controlled variable).
Each monitored variable, such as body temperature, blood
pressure, or blood glucose level
Any disruption that changes a controlled
condition is called a stimulus.
receptor
is a body structure that monitors changes in a controlled
condition and sends input to a control center. (afferent pathway)
afferent pathways - information that flows toward the control center. (nerve impulses or chemical signals).
control center
sets the narrow range or set point within which a controlled condition should be maintained evaluates the input it receives from receptors, and
generates output commands when they are needed.
efferent pathway (away from) - output
effector
is a body structure that receives an output
from the control center and produces a response or effect that
changes the controlled condition.
A negative feedback system
reverses a change in a controlled condition and negates the original stimulus.
ex high BP — Baroreceptors (the receptors), pressure-sensitive
nerve cells located in the walls of certain blood vessels,
detect the higher pressure, which sends nerve impulses
(input) to the brain (control center), which interprets the impulses
and responds by sending nerve impulses (output) to the heart and
blood vessels (the effectors). blood pressure becomes normal again
and homeostasis is restored.
positive feedback system
strengthen or reinforce a change
in one of the body’s controlled conditions.
the control center provides commands
to an effector which produces a physiological
response that ADDS to or REINFORCE the initial change in the
controlled condition
so the response is different than the negative feedback
ex when giving birth first contraction sends input to the control center then the output releases -Oxytocin which causes muscles in the wall of
the uterus (effector) to contract even more forcefully.
- blood clotting is also an example of
a positive feedback system.
anatomical position
Descriptions of any region or part of the human body assume that it is
in a standard position of reference called the
the subject stands erect
facing the observer, with the head level and the eyes facing directly
forward. The lower limbs are parallel and the feet are flat on the floor
and directed forward, and the upper limbs are at the sides with the
palms turned forward
prone
body is lying facedown
supine
body is lying faceup
