Introduction to physiology Flashcards
What is physiology?
the study of the function of the biological structure.
What is the function of platelets?
Platelets help stop bleeding (hemostasis).
How
do platelets stop bleeding?
An injury to a blood vessel initiates the mechanism of hemostasis.When the endothelium of a blood vessel is damaged, receptors on the surface of platelets
bind to exposed collagen activating the platelets to the release chemical signals including
adenosine diphosphate (ADP) which, in turn, activate additional platelets that stick together
until a platelet plug forms.
_______-study of biological structures.
Structure determines function
• Physiological mechanisms are dependent upon biological structures.
• A change in anatomy can have a significant effect on physiology.
o Example: Sickle cell anemia results from a mutation in the gene for hemoglobin.
Anatomy
Physiology is an ________ - integrates function across many levels of organization
integrative science
What are the levels of biological organization?
Chemical Level
Cellular Level
Tissue Level
Organ level
Organ System level
Organism level
What type of level of biological organization is this?
_____-atoms and molecules.
Chemical level
What type of level of biological organization is this?
_____-smallest living units
Cellular level
What type of level of biological organization is this?
_____- group of similar cells that perform a function.
Tissue level
What type of level of biological organization is this?
_____- two or more tissues performing a function
Organ level
What type of level of biological organization is this?
_____- organs that work together for functions
Organ system
What type of level of biological organization is this?
_____- an individual (eleven organ systems in a human).
Organism
_______________-study of electrical activity (eg. voltage and current) in biological
cells and tissues.
• Example: Electrocardiogram is used to measure electrical activity of the heart.
Electrophysiology
______-study of how biological structures change especially during the
embryonic and fetal stages of life.
• Example: At the beginning of the third week of embryonic development the process of
gastrulation forms three distinct tissue types known as the germ layers. The superficial
germ layer known as ectoderm will later differentiate to form the nervous tissue and
epidermis. The middle germ layer known as mesoderm will later differentiate to form
muscles tissues, osseous tissue, and blood vessels. The deepest germ layer known as
endoderm will later differentiate to form the majority of the organs of the digestive
system.
Developmental biology
______-study of the adaptations of organisms to environmental conditions.
• Example: The Bajau, or ‘‘Sea Nomads,’’ that have traditionally obtained food by spear
fishing while holding their breath have larger spleens and an enhanced dive reflex enabling
them to dive for longer periods of time.
o Optional: Learn more by reading the primary article on Canvas
Ecophysiology
_____-study of the functional changes that occur with exercise.
• Example: Exercise increases activity of sympathetic efferent fibers that stimulate the heart
leading to increased cardiac output (rate of blood flowing out of the heart).
Exercisephysiology
______-study of the functional changes in disease.
• Example: Pathophysiology of hypertension in obesity involves elevated adipose tissue
hormones stimulating the sympathetic nervous system and renin-angiotensin-aldosterone
system.
o Optional: Learn more by reading the literature review on Canvas
pathophysiology
What is Homeostasis?
A constant internal environment
Homeostasis:
Mainly controlled by a process called 15)____________ feedback - the output or response of
the effector counteracts the original stimulus, returning the variable to normal limits.
Negative feedback
Homeostasis:
Internal values within the body may vary within narrow limits (for example: body
temperature, pH, blood glucose levels, etc.) These are called _______
variables.
Homeostasis:
a _____ can cause these variables to deviate from their stable condition.
This will trigger a sequence of events (compensatory responses) that will counteract
the change caused by the stimulus to bring the variable back into its normal limits.
stimulus
Homeostasis:
Tends to be stabilizing
o Can be a_______-term immediate response to a stimulus or a long-term adaptation to a
constant stimulus.
§ Example: Regulation of blood pressure during hypotension.
Ø_________: increased activity of sympathetic nervous system
leads to increased cardiac output and vasoconstriction.
Ø __________: increased production of erythropoietin and
renin by the juxtaglomerular cells in the kidneys stimulates red blood
cell production (red bone marrow), sensation of thirst, release of
antidiuretic hormone (brain), and reabsorption of sodium and water
(by distal convoluted tubules and collecting ducts in the kidneys)
increasing blood volume.
short
- Short term response
- Long term adaptation
Components of Homeostatic Control Mechanisms;
______-factor being regulated
§ In this example it would be body temperature
Variable
Components of Homeostatic Control Mechanisms;
_______-produces a change in the variable
§ Exercise could be one stimulus that would cause body temperature to
increase
Stimulus
Components of Homeostatic Control Mechanisms;
_______-detects change in the variable.
§ In this example, thermoreceptors in the skin and hypothalamus
monitor body temperature and they would detect that temperature is
increasing
Sensory or receptor
Components of Homeostatic Control Mechanisms;
_______-communicates the information from the receptor to the
control center.
§ In this example thermoreceptors in the skin relay the signal through
afferent fibers of the PNS and ascending tracts of CNS to reach the
thermoregulatory control center in the hypothalamus. However,
thermoreceptors are also located in thermoregulatory control center
of the hypothalamus. Therefore, there isn’t always a distinct input. If
the receptors are in a different location then the control center your
input is usually a sensory pathway of the nervous system but it depends
on the example.
Input ( Afferent pathway)
Components of Homeostatic Control Mechanisms;
_______-analyzes the information from the receptor and
determines the appropriate response to the change.
§ In this example the thermoregulatory control center is in the median
preoptic nucleus of the preoptic anterior hypothalamic area (POAH).
It will decide that body temperature needs to be lowered and will send
the information to the effector.
Control center
Components of Homeostatic Control Mechanisms;
______-sends/communicates the response instructions
from the control center to the effector.
§ In this example the output would be the efferent pathway of the
nervous system. It would be specifically the sympathetic branch of the
autonomic nervous system traveling to smooth muscle in the blood
vessels and sweat glands
Output
Components of Homeostatic Control Mechanisms;
_____-are organs or glands that carry out the response
from the control center.
§ In this example the effector would be the sweat glands and the blood
vessels in the skin
Effectors
Components of Homeostatic Control Mechanisms;
_____-The action of the effector that will counteract the
stimulus and bring the variable back to its normal value.
§ In this example it would be producing sweat to help cool the body and
the dilation of the blood vessels in the skin that allow more heat to
radiate away from the body. Both these responses will cool the body
and bring the temperature back to normal.
Response
_____-output of effector is amplified or the original
stimulus is intensified
o Variable moves further from set value
o Tends to be destabilizing if it is not self-limiting
o Example: Childbirth
Positive Feedback
_____-reflex that starts the response loop in
anticipation of the stimulus or change
o Example: Increased pulmonary ventilation in anticipation of exercise.
Feed-forward
______-homeostasis can be controlled from outside the organ or
tissue through a reflex or it could be controlled completely within the organ/tissue where the
change occurs.
Sources of Homeostatic Controls
_______-from outside the organ/tissues
o Accomplished by the nervous and endocrine systems. This is also called reflex
control.
o It involves several systems working towards a common goal
§ Example: control of body temperature. This would be considered a
reflex or extrinsically controlled because the change is detected in one
part of the body (the hypothalamus) and then the response involves
other areas such as the blood vessels of the skin and sweat glands
which are located elsewhere and are controlled by the nervous system.
Extrinsic control
_______-from within the organ/tissue (a.k.a local control)
o Self-serving the organ it occurs in
§ Example: Decreased oxygen levels detected within skeletal muscle
tissue can causes vasodilation of local blood vessels so that more
blood flows into the active tissue. The low oxygen levels are detected
and the response occurs all within the skeletal muscle tissue.
Therefore, it is considered locally controlled and does not involve the
nervous or endocrine communicating systems.
Intrinsic Control
