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Atoms/ molecules
Cells
Tissues
Organ
Organ systems
Organisms
Start with air: air from external environment that has O2 comes to the body while CO2 comes out. Occurs at the lungs => respiratory system
O2 goes into blood vessels in circle movement and continues to circulate in order to pump the heart => called a circular system that circulate bloods, nutrients, O2 around, and it delivers to different cells such as nerves, muscles cells, etc…Also, 2 ways communication between cells and circulatory systems
Blood goes around that has filtered at kidney. Filtration occurs that creates filtrate which will travel through and then eventually concentrate because of re-absorption. Filtered into urine => urinary/ or renal system
Nutrients, water, inorganic ions go into the tube and happens:
Secretion (ex: digestive enzymes)
Absorption: nutrients absorb into circulatory system, and distributes to other areas like muscles and other cells in the body
Unabsorbed materials go down along the tube, also known as feces => digestive system
O2 in the lungs, food in stomach = part of external environment
Until food absorbed into the body and bloodstream = internal environment
Kidney: urine is formed from filtration and stored in the bladder. The fluid inside the bladder is an external environment
Human body requires contact with the external environment
Problems: Not all cells are in direct contact w/ external environment
Solutions: fluid compartments => allows for cell communications (eg: one cell is filled w/ fluid, and another cell is filled w/ fluid. The fluids between them can move in and out of the cells, meaning components to be shared and communicated)
Intracellular fluid (ICF)
Extracellular fluid (ECF)
Maintenance of a relatively constant internal environment (meaning to keep internal environment balance)
Unifying them in physiology
Disruption occurs → body no longer at ease → it’s decreased → disease
Two classes:
Intrinsic/ Local controls: Inherent in an organ (ex: blood vessel can open/close by itself)
Extrinsic/ systematic controls:
regulatory mechanisms initiated outside organ
involved a lot of long distance systems: uses endocrine and nervous systems
ex: blood vessels open up by a hormone or electrical impulses caused by a neuron → called extrinsic control since blood vessels are regulated by the outside using other systems
Is the range for a regulated variable that the body wants to maintain
ex:
body temp: 37C
blood glucose: 100 mg/ml
Blood pH: 7.35-7.45
error signals: deviation from the set point
ex: if body temp is supposed to be 37C, but it climbs to 39C, then 2 degree deviation is error signal
once you have error signal, it will take a homeostatic response
Stimulus: deviation/or changes from set point (error signal)
Sensor: detects stimulus
Integrating center
receives inputs from receptors
determines needed output to effectors
usually is the nervous system
Effectors: receives output to respond to stimulus
Blood glucose level is normal. Drinking watermelon juice causes glucose level increases, causing error signals:
Stimulus: glucose from watermelon juice
Sensor: beta cells of pancreas which detect the increase of glucose level in blood
Integrating center: beta cells of pancreas which take information of high blood glucose levels and determine the need output (insulin). Insulin goes to blood and binds to effectors (muscle cells, adipose tissues, liver cells,…) since output communicates to the effectors
Effectors: after receiving insulin, the effectors respond to the glucose levels by uptaking glucose and remove it from the blood, lowering your blood glucose and getting back to the initial set point
Two types:
Negative feedback
Positive feedback
response moves the system in the opposite direction of the initial change
stabilizing: keeps things at a particular set point since whenever deviation sets a particular direction, the responses move it the opposite direction
More common in the body
Ex:
Blood glucose level (fig: initial change is increase blood glucose, but the response is decrease blood glucose in opposite direction)
Regulate body temp
body temp goes up → responses move temp down
cold → temp down → response move temp up → shivering
Response moves the system in the same direction as the inital changes
Directional
Less common
Ex:
Childbirth: keeps increasing oxytocin until done in delivery of the baby
Ovulation
Blood glucose levels: cannot be regulated normally
Urine volume: urine draws water away from your body and dehydrates, causing urine to be higher volume => Diabetes people usually urinate more frequently
Excessive thirst
Excessive fluid loss
Eventually all body system affected
4 types:
Diabetes Mellitus Type I
Diabetes Mellitus Type II
Gestational Diabetes
Diabetes Insipidus
Inadequate insulin production (generally in younger)
(eg: insulin produced by beta cells in pancreas. For some reasons, the immune system starts to attack the beta cells, meaning they no longer have many beta cells and resulting in inadequate insulin production. Since you don’t produce enough beta cells in pancreas, the glucose is to high, leading to diabetes)
Insulin dependent
Body cells lose response to insulin
Non-insulin dependent
Most common
Inadequate antidiuretic hormone secretion → high urine volume
Rare
Anti-diurectic is a hormone that stops urinating, hence it makes you re-absorb your fluids more. No issues w/ insulin or glucose levels, but it’s about high urine volume
Obesity:
High fat content relative to lean body mass
Body mass index (BMI): 30-39
BMI = body weight (kg) / height (m^2)
Sedentary lifestyle (inactive lifestyle)
fluids outside cells
includes:
Plasma: liquid (non-cellular) portion of blood
ex: blood vessel has red blood cell and fluid surrounding those red blood cells. This fluid is called plasma and it’s a type of ECF
Interstitial fluid (ISF): fluid surrounding cells anywhere in the body, but not in blood vessel
Note 
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