Physiology Lecture Exam 1

Chronic elevation of cortisol leveled is most likely associated with:

Immunosupression

Why can humans survive for weeks without food but only days without water?

Triglycerides stored in adipose tissue provide a high-density, long-term energy source.

Which statement best defines homeostasis?

The body's ability to maintain a relatively stable internal environment despite external changes

Which functional group is considered acidic because it ionizes to release H+  ions into a solution?

Carboxyl

The pancreas releases insulin into the bloodstream after a meal. Which transport mechanism is responsible?

Exocytosis

A patient develops damage to the tight junctions in their intestinal lining. What is the most likely consequence?

Increase leakage of substances

In the context of human physiology, how is the concept of homeostasis best described?

The body's process of maintaining a stable internal state despite external changes.

A student leaves an air-conditioned classroom and walks outside on a hot day. Which sequence best describes the body's response?

Increased temperature → thermoreceptors → hypothalamus → sweat glands → cooling

Which of the following elements accounts for the largest percentage of atoms in the human body by mass?

Oxygen (O)

Insulin helps increase glucose uptake into cells primarily by:

Increasing facilitated diffusion through GLUT transporters

Which component of the plasma membrane is primarily responsible for forming the semipermeable barrier that prevents stomach acid from leaking into surrounding tissues?

The phospholipid bilayer

A liver cell exposed to alcohol for many years would likely increase the amount of which organelle?

Smooth ER

In the context of fat digestion, what is the function of the lipoprotein known as a Chylomicron?

 

Transporting assembled triglycerides from the intestines to the body.

A person has not eaten for three days. Which nutrient provides the majority of ATP?

Lipids

During the regulation of high blood glucose, which cells act as the sensor and control center?

β-cells of the pancreas

In the Luteal Phase of the menstrual cycle, what is the primary role of the corpus luteum?

To produce progesterone and maintain the uterine lining

During exposure to a hot environment, sweating is classified as a(n):

Effector response

What is the primary role of HDL (High-Density Lipoprotein) in the human body?

It returns excess cholesterol from the tissues back to the liver.

A poison completely blocks the Na⁺/K⁺ ATPase pump. Which cell type would be affected most immediately?

Neurons

A pregnant woman is diagnosed with a mitochondrial disease. Why is there concern that her children may inherit the condition?

Most mitochondria are inherited from the mother’s egg

Regular exercise can reduce the risk of Type II diabetes partly because exercise:

Increases GLUT4 transporters and mitochondrial density

A patient with severe pneumonia is placed on supplemental oxygen. Why is oxygen essential for ATP production?

Oxygen is the final electron acceptor in the ETC

How do combined birth control pills prevent pregnancy?

They trick the brain into thinking the body is already pregnant.

What happens to the GLUT4 transporter in muscle cells when insulin binds to its receptor?

 

It migrates to the cell membrane via exocytosis.

Which component of a feedback loop determines the appropriate response to a stimulus?

Control Center

The release of oxytocin during childbirth is an example of which type of feedback, and why?

Positive feedback, because it increases the intensity of contractions to reach the endpoint of delivery.

A patient recovering from surgery is advised to consume adequate dietary protein. Why are proteins important during recovery?

They supply amino acids

A student skips breakfast and lunch before taking an afternoon exam. Which sequence most likely occurs to maintain blood glucose homeostasis?

Glucagon release → Glycogen breakdown

A white blood cell engulfing a bacterium is an example of which type of vesicular transport?

Phagocytosis

Botulinum toxin prevents the release of acetylcholine from neurons. Which transport process is directly inhibited?

Exocytosis

A patient has a disease that destroys mitochondria in their muscle cells. Which symptom would be most likely?

Severe fatigue and muscle weakness

A patient presents with fatigue due to a deficiency in a vitamin required for NAD production. Which vitamin is deficient?

B3 (Niacin)

How do triglycerides compare to starch (carbohydrates) in terms of energy storage density?

Triglycerides provide about 2.5× more energy per gram than starch.

A teenager consistently sleeps only four hours per night and rarely exercises. Which endocrine response may be reduced?

Growth hormone secretion

Which scenario best demonstrates interaction between the nervous and endocrine systems?

The hypothalamus detects dehydration and stimulates ADH release.

Which of the following factors would most likely decrease the rate of diffusion for a specific molecule across a membrane?

An increase in the molecular size of the solute

A patient with Type II diabetes has elevated blood glucose but complains of fatigue. What best explains this symptom?

Cells cannot effectively take up glucose

According to the Endosymbiotic Theory, what evidence suggests that mitochondria were once independent bacteria?

They contain their own circular DNA and ribosomes.

A nurse works overnight shifts for several years. Which endocrine rhythm is most likely disrupted?

Cortisol circadian cycle

Which sequence correctly describes a feedback loop?

Stimulus → Sensor → Control Center → Effector → Response

During blood clotting, platelets release chemicals that recruit additional platelets. This is an example of:

Positive feedback

A patient takes atorvastatin (Lipitor) to reduce cholesterol levels. How does this medication work?

It inhibits cholesterol synthesis.

A patient develops severe diarrhea after infection with cholera. Cholera toxin causes excessive chloride ion movement out of intestinal cells. Water follows these ions into the intestine. Which two transport processes best explain this fluid loss?

Diffusion of ions and osmosis of water

After exercising, a runner develops a fever. Which change would most likely increase the rate of diffusion of oxygen into body tissues?

Increased temperature

During severe exercise, muscle cells require rapid oxygen delivery. Which cellular characteristic best supports this function?

High surface area-to-volume ratio

A patient consumes a meal rich in carbohydrates. Which process is most likely stimulated?

Glycogen synthesis

A child is entering puberty. Which hormonal pathway is primarily responsible for initiating reproductive maturation?

GnRH → FSH/LH

Why can humans survive for weeks without food but only days without water?

Triglycerides stored in adipose tissue provide a high-density, long-term energy source.

A patient is given a medication that damages the alveolar membrane in the lungs. Which physiological process would be most directly affected?

Oxygen diffusion into blood

A red blood cell is placed in a solution containing a hypertonic salt concentration compared to the cell itself. The cell will:

Shrink

A newborn has a mutation affecting anchoring junction proteins in the skin. What symptom would most likely occur?

Skin that tears or blisters easily

A patient has been fasting for several days. Which fuel source becomes increasingly important for the brain?

Ketone Bodies

A marathon runner consumes a carbohydrate-rich diet for three days before a race. What is the primary physiological benefit?

Increase glycogen storage and delayed fatigue

A pregnancy test detects elevated hCG levels. What is the primary role of hCG early in pregnancy?

Maintain progesterone production by the corpus luteum

Which of the following is the primary goal of negative feedback?

Maintain a physiological variable near its set point

Which of the following would most likely occur during prolonged exposure to cold temperatures?

Increased shivering and vasoconstriction

A patient reports bloating, gas, and diarrhea after consuming ice cream. Symptoms improve when they avoid dairy products. Which explanation best accounts for the patient's symptoms?

Inability to digest lactose into absorbable monosaccharides

The Na+/K+ ATPase pump is a classic example of active transport. For every cycle of the pump, what is the net movement of ions?

 

3 Na+  ions are moved out of the cell and 2 K+ ions are moved in

What is the primary difference between simple diffusion and facilitated diffusion?

Facilitated diffusion requires specific membrane proteins to move substances

How does the bacterium Helicobacter pylori contribute to the development of peptic ulcers at the cellular level?

It weakens the tight junctions between gastric epithelial cells, allowing stomach acid to leak into underlying tissues

After eating a cheeseburger, triglycerides are digested into:

Fatty acids and glycerol

How does the hormone Prolactin relate to the neurotransmitter Dopamine in the context of lactation?

A decrease in Dopamine allows Prolactin levels to rise.

During labor, the baby's head stretches the cervix and uterine contractions become progressively stronger. This is an example of:

Positive Feedback

A rise in body temperature above normal represents a:

Stimulus

A nurse explains to a patient that hormones act as chemical messengers. Which sequence best describes cellular communication?

Signal → Receptor → Response

A patient has a genetic defect in calcium pumps within muscle cells. Which symptom would most likely occur?

Difficulty relaxing muscles

The adrenal cortex produces large quantities of steroid hormones. Which organelle would be especially important in these cells?

Smooth ER

In the PIP2-Ca2+  signaling pathway, what is the specific role of Inositol Trisphosphate (IP3)?

Releasing Ca2+ from the endoplasmic reticulum

What is the primary distinction between negative and positive feedback mechanisms?

Negative feedback maintains a set point, while positive feedback amplifies a process toward a specific conclusion.

How do enzymes increase the rate of biological reactions?

They lower the activation energy required for the reaction to proceed.

A patient with pneumonia has fluid-filled alveoli that slow the movement of oxygen from the lungs into the bloodstream. Which transport mechanism is primarily impaired?

Diffusion

A patient with uncontrolled hypertension develops swelling in both ankles. Which transport mechanism most directly contributes to this edema?

Filtration

What is the primary cellular consequence of the missing digestive enzymes in Tay-Sachs Disease?

Lysosomes fail to recycle cellular waste, leading to the toxic buildup of fatty substances in nerve cells.

Following a large Thanksgiving dinner, which hormone is expected to be elevated?

Insulin

In the Electron Transport Chain (ETC), how many ATP molecules are typically generated from a single FADH2 molecule?

2 ATP

A student eats a large Thanksgiving dinner and then takes a nap. Which hormonal response is most likely helping restore homeostasis?

Increased insulin release promoting glucose storage

Which of these biological processes is driven by a positive feedback loop?

Uterine contractions during childbirth

In the homeostatic regulation of blood sugar, what type of feedback is most likely used to maintain a stable level?

Negative Feedback

A patient recovering from surgery is advised to consume adequate dietary protein. Why are proteins important during recovery?

They supply amino acids

A protein is successfully produced in the rough ER but never reaches the plasma membrane. Which organelle is most likely malfunctioning?

Golgi apparatus

Red blood cells have no mitochondrial function. Which ATP-producing pathway would still function normally?

Glycolysis

Which of the following characteristics distinguishes endocrine glands from exocrine glands?

Endocrine glands secrete hormones directly into the bloodstream.

Which structure serves as the primary control center for thermoregulation?

Hypothalamus

A student experiences prolonged academic stress and subsequently develops shingles. Which explanation is most physiologically accurate?

Stress can elevate cortisol, which can suppress immune function

Why is the Na⁺/K⁺ ATPase pump considered active transport?

It requires ATP to move ions against their concentration gradients

How does the Cholera toxin specifically lead to severe dehydration in the human body?

It causes an uncontrolled efflux of Cl− ions, forcing water to follow via osmosis

A mutation prevents insulin from being released from pancreatic cells, even though insulin is produced normally. Which process is most directly affected?

During prolonged starvation (days without food), what is the role of Ketone bodies?

 

They act as an alternative fuel for the brain to spare muscle protein.

A college student rapidly runs up five flights of stairs and develops a burning sensation in their leg muscles. What is the primary cause?

H+ accumulation from anaerobic metabolism

A patient moves from a warm room into a freezing environment. Which endocrine pathway would help maintain body temperature?

TRH → TSH → T3/T4

Why can't we absorb a steak directly into our bloodstream?

It must be broken down into monomers

A patient with chronic alcohol abuse develops liver damage. Which organelle has likely been heavily utilized in detoxification?

Smooth ER

A cancer patient experiences severe muscle wasting. Which metabolic process is contributing most directly?

Protein breakdown

A patient experiences severe blood loss after a car accident. Which statement best demonstrates how the nervous and endocrine systems work together to maintain homeostasis?

The nervous system detects stress, while endocrine hormones help sustain the body's response.

A patient develops a high fever that causes partial protein denaturation. Which protein characteristic is most likely disrupted?

Tertiary protein structure

Which cell would be expected to contain the most rough ER?

Plasma cell

During the postabsorptive (fasting) state, which hormone is predominantly active to maintain blood glucose levels?

Glucagon

patient reports fatigue, weight loss, and chronically low blood pressure. Laboratory tests reveal low cortisol levels. Which structure is most likely failing?

Adrenal cortex

A patient has been fasting for 16 hours before a medical procedure. Which response would most likely occur?

α-cells release glucagon

Which component of a feedback loop determines the appropriate response to a stimulus?

Control center