chapter 1 Flashcards
homeostasis
the maintenance of a relatively
constant internal environment despite fluctuations in the external
environment.
Anatomy
the scientific discipline that investigates the
structure of the body—for example, the parts and chambers of the heart.
The word anatomy means
to dissect, or cut apart and separate, the parts of the
body for study.
anatomy examines the relationship between
the
structure of a body part and its function.
two basic approaches to the study of anatomy
Systemic and regional anatomy
Systemic anatomy
the study of the body by systems, such as the cardiovascular, nervous, skeletal, and muscular
systems. It is the approach taken in this textbook.
Regional anatomy
the study of the organization of the body by areas.
two general ways to examine the internal structures of a living person
surface anatomy and anatomical imaging
Surface anatomy
the study of external features, such as bony projections, which serve as landmarks for locating deeper structures.
Anatomical imaging
involves the use of x-rays, ultrasound,
magnetic resonance imaging (MRI), and other technologies to create pictures
of internal structures, such as when determining if a bone is broken or a
ligament is torn.
Both surface anatomy and anatomical imaging provide
important information for diagnosing disease
Physiology (study of nature)
the scientific discipline that deals with the processes or functions of living things.
it is important in physiology to recognize structures as
dynamic
There are two major goals when studying physiology
examining the body’s responses to stimuli and examining the body’s maintenance of stable internal conditions.
Human physiology
study of humans
cellular physiology
focuses on processes inside cells such as the manufacturing of
substances, including proteins.
systemic physiology
focuses on the functions of organ systems.
What are the 6 levels of organization in the body
chemical, cell, tissue, organ, organ system, and organism
Chemical level (simple ver)
atoms combine to form molecules
cell level (simple ver)
molecules form organelles, such as mitochondria and nucleus, which make up cell.
tissue level (simple ver)
similar cells and surrounding materials make up tissue.
organ level (simple ver)
different tissue combines to form organs
organ system (simple ver)
organs make up organ system
organism
organ systems make up an organism
Levels of Organization for the Human Body
The simplest level of organization in the human body is the atom. Atoms combine to form
molecules. Molecules aggregate into cells. Cells form tissues, which combine with other tissues to form organs. Organs work in groups called organ systems. All organ systems work together to form an organism.
Chemical Level
The structural and functional characteristics of all organisms are determined by their chemical makeup.
The chemical level of organization involves how atoms,
such as hydrogen and carbon, interact and combine into molecules.
This is important because
a molecule’s structure determines its function.
collagen molecules are strong, ropelike fibers that give skin structural strength and flexibility.
With aging, the structure of collagen changes, and the skin becomes fragile and more easily torn during everyday activities.
Cell Level
Cells are the basic structural and functional units of organisms, such as plants and animals.
Most cells contain smaller structures inside them, called
Organelles
Organelles carry out particular functions
such as digestion and movement, for the cell.
the nucleus
contains the cell’s hereditary information
mitochondria
manufacture adenosine triphosphate (ATP)
ATP
a molecule cells use for a source of energy.
Although cell types differ in their
structure and function, they have many characteristics in common.
Microbes in your body
more microbial cells than human cells in your body
every cell in your body
there is one microbial cell
40 trillion microbial cells,
which collectively can account for 2 to 6 pounds of your body weight.
A microbe is
any life form that can only be seen with a microscope (for example, bacteria, fungi, and protozoa).
All living organisms fit into one of three domains of living organisms:
(1) Bacteria, (2) Archaea, and (3) Eukarya.
Bacterial cells’ genetic material
is not separated from the rest of the cell by a barrier.
bacterial cells have
far fewer separate structures made of membrane for carrying out the cell’s metabolic processes than eukaryotic cells.
Archaea cells are constructed
similarly to
bacteria; however, they share certain structures, called ribosomes, with eukaryotic cells.
the term prokaryotic is used to describe
bacterial and archaea cells.
Eukarya cells
which include human cells, have the most structural complexity with many smaller structures, called organelles, surrounded by membranes.
These smaller structures conduct
the metabolic processes of the cell.
size differences between bacteria and archaea and cells of eukaryotes is quite evident
with most eukaryotic cells being significantly larger than most prokaryotic cells.
The total population of microbial cells on the human body is
microbiota
the collection of all the microbial cell genes is known as
the microbiome
The microbiota includes
so-called good bacteria, which do not cause disease and may even help us.
pathogenic,
or bad bacteria
What did scientists learn from the Human Microbiome Project?
Human health is dependent upon the health of our microbiota, especially the “good” bacteria.
the human microbiome is intimately involved
in the development and maintenance of the immune system.
more evidence is mounting for a correlation between
a host’s microbiota, digestion, and metabolism.
microbial genes are
more responsible for our survival than human genes are.
There are even a few consistent pathogens that are present without causing disease,
suggesting that their presence may be good for us. However, there does not seem to be a universal healthy human microbiome.
Instead of being a detriment, this variation may actually be very useful
for predicting disease. There seems to be a correlation between autoimmune and inflammatory diseases (Crohn’s disease, asthma, multiple sclerosis), which have become more prevalent, and a “characteristic microbiome community.”
Tissue level
A tissue is a group of similar cells and the materials surrounding
them.
The characteristics of the cells and surrounding materials determine
the functions of the tissue.
The many tissues that make up the body are classified into four primary types:
(1) epithelial, (2) connective, (3) muscle, and (4) nervous.
Organ level
An organ (OR-gan; a tool) is composed of two or more tissue types that together perform one or more common functions.
Organ System Level
An organ system is a group of organs that together perform a common function or set of functions.
eleven major organ systems
(1) integumentary, (2) skeletal, (3) muscular, (4) nervous, (5) endocrine, (6) cardiovascular, (7) lymphatic, (8) respiratory, (9) digestive, (10) urinary, and (11) reproductive
Major Organs of the Body
brain, lungs, heart, liver, pancreas, spleen, stomach, gallbladder, kidneys, large intestine, small intestine, urinary bladder, and urethra.
Integumentary System des
Provides protection, regulates temperature, prevents water loss, and helps produce vitamin D.
Integumentary system
Consists of skin, hair, nails, sebaceous glands, and sweat glands.
skeletal system des
Provides protection and support, allows body movements, produces blood cells, and stores minerals and adipose tissue.
skeletal system
Consists of bones, associated cartilages, ligaments, and joints.
muscular system des
Produces body movements, maintains posture, and produces body heat
muscular system
Consists of muscles attached to connective tissue sheets or the skeleton by tendons.
nervous system des
A major regulatory system that detects sensations and controls movements, physiological processes, and intellectual functions.
nervous system
Consists of the brain, spinal cord, nerves, and sensory receptors.
Endocrine system des
A major regulatory system that influences metabolism, growth, reproduction, and many other functions.
Endocrine system
Consists of endocrine glands, including the hypothalamus, pituitary, thyroid gland, adrenal gland, gonads, and other tissues that secrete hormones.
Cardiovascular System des
Transports nutrients, waste products, gases, and hormones throughout the body, plays a role in the immune response and the regulation of body temperature.
Cardiovascular system
Consists of the heart, blood vessels, and blood.
Lymphatic system des
Removes foreign substances from the blood and lymph, combats disease, maintains tissue fluid balance, and absorbs dietary fats from the digestive tract.
lymphatic system
Consists of the lymphatic vessels, lymph nodes, thymus, spleen, and other lymphatic tissues.
Respiratory System des
Exchanges oxygen and carbon dioxide between the blood and air and regulates blood pH.
respiratory system
Consists of the lungs, diaphragm, and respiratory passages.
Digestive System des
Performs the mechanical and chemical processes of digestion, absorption of nutrients, and elimination of wastes.
digestive system
Consists of the mouth, esophagus, stomach, intestines, liver, gallbladder, and other accessory organs.
Urinary system des
Removes waste products from the blood and regulates blood pH, ion balance, and water balance.
Urinary system
Consists of the kidneys, ureters, urethra, and urinary bladder.
Female reproductive system des
Produces oocytes and is the site of fertilization and fetal development, produces milk for the newborn: produces hormones that influence sexual function and behaviors
Female reproductive system
Consists of tho ovaries, uterine tubes, uterus, vagina, mammary glands, and associated structures.
Male reproductive system des
Produces and transfers sperm cells to the female and produces hormones that influence sexual functions and behaviors.
Male reproductive system
Consists of the testes, accessory structures, ducts, and penis.
organism level des
An organism is any living thing considered as a whole, whether composed of one cell, such as a bacterium, or of trillions of cells, such as a human.
The human organism is
a network of organ systems that are mutually dependent upon one another.
six essential characteristics of life
organization, metabolism, responsiveness, growth, development, (differentiation), reproduction
Organization
refers to the specific interrelationships among the individual parts of an organism, and how those parts interact to perform specific functions.
All organisms are composed of one or more cells
In turn, cellular function depends on the precise organization of large molecules.
Metabolism
the ability to use energy to perform other vital functions, such as growth, movement, and reproduction.
Human cells possess specialized proteins that can
break down food molecules to use as a source of energy.
Responsiveness
is an organism’s ability to sense changes in the external or internal environment and adjust to those changes.
Organisms can also make adjustments that maintain their internal environment.
For example, if our body temperature rises, sweat glands produce sweat, which can lower body temperature down to the normal range.
Growth
refers to an increase in the size or number of cells, which produces an overall enlargement in all or part of an organism, cell size, or the amount of substance surrounding cells.
Development
includes the changes an organism undergoes through time, beginning with fertilization and ending at death.
Development usually involves
growth, but it also involves differentiation.
Differentiation
involves changes in a cell’s structure and function from an immature, generalized state to a mature, specialized state.
following fertilization, immature cells differentiate to become specific
types of cells, such as skin, bone, muscle, or nerve cells.
These differentiated cells form tissues and organs.
Reproduction
the formation of new cells or new organisms. Reproduction of cells allows for growth and development. Formation of new organisms prevents extinction of species.
homeo
the same
stasis
stop
homeostasis
the maintenance of a relatively constant environment within the body.
To achieve homeostasis,
the body must actively regulate body conditions that are constantly changing.
Body temperature is one of our
body’s variables
changes in body conditions are called variables
because their values are not constant
For cells to function normally,
the volume, temperature, and chemical content of the cells’ environment must be maintained within a narrow range.
homeostatic mechanisms
that maintain normal body temperature include sweating or shivering to maintain body temperature near an ideal normal value, or set point
Most homeostatic mechanisms are regulated by
the nervous system or the endocrine system
homeostatic mechanisms are not able to maintain body temperature
precisely at the set point.
.
body temperature increases and decreases slightly around the set point, producing
a normal range of values
As long as body temperatures remain within this normal range,
homeostasis is maintained
fluctuations are minimal.
Fluctuations happens but minimal lang
Our average body temperature is
98.6°F
Homeostasis
the maintenance of a variable around an ideal normal value, or set point.
The value of the variable fluctuates around
the set point to establish a normal range of values.
one of the mechanisms by which homeostasis is maintained.
Negative feedback
Receptors signal the control center,
which regulates the action of the effectors.
Negative feedback stops the sweating
the body temperature returns to normal.
Positive feedback is also a type of mechanism that works to maintain homeostasis.
Receptors signal the control center that the cervix is being stretched, which results in the control center sending signals to increase the contractions of the uterus.
The organ systems
help keep the body’s internal environment relatively constant.
the digestive, respiratory, cardiovascular, and urinary systems function together
so that each cell in the body receives adequate oxygen and nutrients while also ensuring that waste products do not accumulate to a toxic level.
If body fluids deviate from homeostasis,
body cells do not function normally and can even die.
Disease
disrupts homeostasis and sometimes results in death.
Most systems of the body are regulated by
negative-feedback mechanisms which maintain homeostasis.
negative
“to decrease.”
Negative feedback
when any deviation from the set point is made smaller or is resisted.
Negative feedback does not prevent variation
but maintains variation within a normal range.
example of a negative-feedback mechanism
maintenance of normal body temperature
Normal body temperature is critical to our health because
it allows molecules and enzymes to keep their normal shape so they can function optimally
An optimal body temperature
prevents molecules from being permanently destroyed.
if the body is exposed to extreme heat,
the shape of the molecules in the body could change, which would eventually prevent them
from functioning normally.
Most negative-feedback mechanisms have three components:
receptor, control center, effector
receptor
which monitors the value of a variable, such as body temperature, by detecting stimuli
control center
such as part of the brain, which determines the set point for the variable and receives input from the receptor about the variable
effector
such as the sweat glands, which can adjust the value of the variable when directed by
the control center, usually back toward the set point.
A changed variable
stimulus because it initiates a homeostatic mechanism.
Several negative-feedback mechanisms regulate
body temperature
Normal body temperature
depends on the coordination of multiple structures, which are regulated by the control
center (the hypothalamus)
Receptors in the skin monitor body temperature.
If body temperature rises, the receptors send a message to the control center.
The control center compares
the value of the variable against the set
point.
If a response is necessary,
the control center will stimulate the effectors, the sweat glands, to produce their response, which is secretion of sweat.
Once the value of the variable has returned to the set point,
the effectors do not receive any more information from the control center. For body
temperature, this means that secretion of sweat stops.
Often there is more than one effector for a particular homeostatic
mechanism.
In these cases the control center must coordinate the effectors’
responses.
cooling the body involves not only the production of
sweat by the sweat glands,
but also the action of the blood vessels to alter
blood flow to the skin. Once body temperature has returned to normal, the
effectors stop.
This is the hallmark of negative feedback
effectors stop their response once the variable has returned to its set point. They do not produce an indefinite response
1
Body temperature is within its normal range.
2
Body temperature increases outside the normal range, which causes homeostasis to be disturbed.
3
The body temperature control center in the brain responds to the change in body temperature.
4
The control center causes sweat glands to produce sweat and blood vessels in the skin to dilate.
5
These changes cause body temperature to decrease. (6) Body temperature returns to its normal range, and homeostasis is restored. Observe the responses to a decrease in body temperature outside its normal range
