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What is physiology?
The study and function of organisms
"How's and why's of the body"
Structural Levels of Organization
Atoms/molecules (building blocks of matter)
Cells (basic unit of life)
Tissues (group of cells working together)
Organs (several types of tissues combine together to perform a function)
Organ systems
Organisms
External Environment
Components outside the body
Ex: air, nutrient, water, inorganic ions, urine, feces
Internal Environment
Components inside the body
Ex: cells, fluid.
What are the external and internal environments separated by?
Epithelium
Ex: skin, lining of lungs, intestinal tract, and kidney tubules
Major Concept...
The human body requires contact with the external environment
Problem: not all cells are in direct contact w/external environment
Solution: Fluid compartments -> allow for cell communication
components to be shared between 2 cells
Fluid compartments of the body: Total Body Water (TBW)
Volume of water contained in all the body's compartments
All H2O that's part of internal environment (the yellow from diagram Slide 8)
What does TBW include?
Intracellular fluid (ICF)
Extracellular fluid (ECF)
What is intracellular fluid?
Fluid INSIDE cells
What is extracellular fluid?
Fluid OUTSIDE cells (surrounding cells)
Includes:
Plasma
Interstitial fluid (ISF)
What is plasma?
Liquid (non-cellular) portion of blood
a type of ECF
“fluid surrounding cells but in blood”
What is interstitial fluid (ISF)?
Fluid (outside the blood) surrounding cells
a type of ECF
Now that cells can communicate, what is the goal??
Homeostasis!!
What is homeostasis?
Maintenance of a relatively constant INTERNAL environment (balance)
A unifying theme in physiology
Disruption -> disease
Homeostatic Control Systems
Regulatory responses to maintain homeostasis
Classes of Homeostatic Control Systems
Intrinsic/Local controls (small scale)
Extrinsic/Systemic controls (involves multiple systems)
Intrinsic/Local Controls
Inherent IN an organ
control @ the local level (organ level)
regulating by itself
ex: BV dilating/constricting b/c it senses chemical change
Extrinsic/Systemic Control
Regulatory mechanisms initiated OUTSIDE organ
uses endocrine and nervous system
Ex: hormones, action potentials, or neurons to regulate a particular organ
coordinates response from several organs -> to achieve common goal
Regulated Variables
Conditions regulated by homeostatic control
Ex: Temperature, pH, salinity, dissolved gas concentration, nutrient and waste concentration...
What is a set point?
Range for a regulated variable the body wants to maintain
Ex:
Body Temperature: 37 C
Blood glucose: 100 mg/dL
Blood pH: 7.35-7.45
What happens if you go out of the range?
Error signal
Deviation from the set point
Homeostatic Response Components
Stimulus
Change from set point (error signal)
Sensor (Detects stimulus)
Detects stimlulus
Integrating Center
Receives input from receptors
Determines needed output to effectors
Usually a part of the nervous system
Effectors
Receives output to respond to stimulus
Ex:
Stimulus = increased glucose
Sensor and Integrating center: Beta Cells from Pancreas
Output = Insulin, which binds to effectors
Effectors = Cells of body -> removes glucose from blood and take into their own cells, which lowers blood glucose
What is Feedback?
Response made after change detected
What are types of feedback?
Negative feedback
Positive feedback
What is Negative Feedback?
Response moves the system in the opposite direction of initial change
Stabilizing
More common
Ex: Body temperature and blood glucose level
What is Positive Feedback?
Response moves the system in the same direction as the initial change
Directional (until you break the feedback loop, it will continue going in that direction)
Less common
Ex: Child birth, ovulation, fever, blood clotting
What is diabetes?
Metabolic disease affecting:
Blood glucose levels (usually higher levels)
Urine volume (increases)
What are the results of diabetes?
Excessive thirst (dehydrated)
Excessive fluid loss
Eventually all body systems affected
Ex: increased glucose can damage neurons
What are the different types of diabetes?
Diabetes Mellitus Type I
Diabetes Mellitus Type II
Gestational Diabetes
Diabetes Insipidus
What is Diabetes Mellitus Type I?
Inadequate insulin production
Insulin DEPENDENT
autoimmune disease
beta cells don't produce insulin, effector cells fine, must inject insulin
What is Diabetes Mellitus Type II?
Body cells LOSE RESPONSE to insulin
Non-insulin dependent
MOST COMMON
usually happens later on in life
beta cells okay
effector cells decreased or damaged (problem w/receptor)
What is Gestational Diabetes?
Temporary loss of sensitivity to insulin due to hormonal changes
Mimics Type II
What is Diabetes Insipidus?
Inadequate anti-diuretic hormone secretion -> HIGH URINE VOLUME
RARE
Ex:
ADH = Vasopressin
Diuretic = what causes you to urinate
anti = stops urinating, makes you reabsorb fluids more
inadequate ADH = will not reabsorb H2O and it will turn into urine
How can you develop diabetes?
Obesity (diet) and Sedentary lifestyle
High fat content relative to lean body mass
Body mass index (BMI) 30-39
*BMI = body weight (kg) / height (m)^2
ECF includes all of the following except...
A) ISF
B) ICF
C) plasma
D) all of the above is part of ECF
Homeostasis......
A) Uses only intrinsic control mechanisms
B) Is the maintenance of a relatively constant external environment
C) Is a unifying theme in physiology
D) All of the above
The amount of deviation from a set point is the...
A) error signal
B) regulated variable
C) sensor
D) effector
Which of the following is not true of positive feedback?
A) It is less common
B) It moves the system in the same direction as the stimulus
C) It is stabilizing
D) It includes ovulation
Which type of diabetes results in high urine volume due to inadequate anti-diuretic hormone secretion?
A) Diabetes Mellitus Type I
B) Diabetes Mellitus Type II
C) Gestational Diabetes
D) Diabetes Insipidus
Note 
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