PHSL 1010 Exam 1 Questions And Accurate Answers
2025-2026
The law of mass balance states - ANSWER if a substance is to remain constant any gain
must be offset by an equal loss
Law of Mass Balance Equation - ANSWER existing body load + intake or metabolic
production (ex: food, liquid, air, through skin) = excretion or metabolic removal (through
kidneys, liver, lungs, skin)
Comparing Concentrations of Na+, Cl-, K+ in ECF vs. ICF ANSWER Na+ high in ECF, low
in ICF
Cl- high in ECF, low in ICF, but lower than Na+ for both
K+ low in ECF, high in ICF
Control systems ANSWER keep regulated variables within the normal range, near set
point or optimal value
What is the elements of a control system? - ANS Input signal [Ex: fluid imbalance],
integrating signal [Ex: nervous/endocrine system], output signal, response [Ex: breather
faster, hr increases]
What is the elements of a response loop? - ANS Stimulus, sensor, input signal,
integrating center, output signal, target, response
Negative feedback vs. positive feedback loop - ANS Negative feedback stabilizes a
variable, positive feedback reinforces stimuli
Steps of a negative feedback loop - ANSWER Initial stimulus --> response --> decrease
,stimulus --> response loop turns off
Steps of a positive feedback loop - ANSWER Initial stimulus --> response --> amplified
stimulus --> positive feedback cycle amplifies the response
-an external influence is needed to turn off a positive feedback cycle
Example of Positive Feedback Loop - ANSWER Contractions of the uterus during child
birth
cervical stretch --> stimulates oxytocin release --> causes uterine contractions -->
pushes baby against the cervix --> causes cervical stretch etc. until baby is delivered
Example of Negative Feedback Loop - ANSWER Regulating blood sugar
What does the body do in response to high blood glucose levels? ANSWER Insulin
released by beta cells, liver cells bind with insulin --> converted into glycogen --> blood
glucose level goes down --> less insulin released
What happens when the blood glucose is low? -ANSWER Alpha cells release glucagon
--> acts on target cells in liver --> liver cells break glucagon down to glucose --> blood
glucose levels increase --> less glucagon is released
Type 1 vs. Type 2 Diabetes -ANSWER Type 1: no insulin is produced therefore
insulindependent
Type 2: insulin is produced, but target cells don't take up glucose
Axes of a graph - ANSWER x axis is independent variable (ex: time), y axis is dependent
variable (varies)
Four major tissue types - ANSWER Epithelial, connective, muscle, and nervous
, Characteristics of epithelial tissue - ANSWER 1. Typically covers a surface as a layer of
cells
2. Cells are tightly packed next to each other (little intracellular space
3. Cells are held together by surface specializations
4. Rests on basal lamina (seals
5. Always avascular: nutrition diffuses through basal lamina
7. Many involve epithelial specializations (sight, taste, smell)
Classification of Epithelial Tissue - ANSWER 1. Number of cell layers (simple= one layer,
stratified = multiple layers)
2. Shape of the cells (squamous = flat, cuboidal = square, columnar = rectangular)
Where would you find simple squamous cells? - ANS blood vessel, endothelium
Where would you find simple cuboidal cells? - ANS kidney tubules
Where would you find simple columnar cells? - ANS Small intestine
Where would you find pseudostratified columnar cells? - ANS Respiratory tract (have
goblet cells which secrete mucus)
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