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Physiology Quiz

Human Physiology — Exam Essentials

Physiology is the study of how the body's cells, tissues and organs work and stay balanced. Your request didn't name a specific topic, so these notes cover the foundation — homeostasis and the major organ systems (cardiovascular, respiratory, nervous, renal, endocrine and digestive) — with the key numbers and terms exams focus on, plus a practice set. Reply if you'd like a deep-dive on any one system.

Homeostasis — The Central Idea

Homeostasis is the maintenance of a stable internal environment despite changing external conditions. Most physiology is an example of it in action.

  • Negative feedback restores a set point (e.g. temperature, blood glucose, blood pressure) and is by far the commonest control mechanism.
  • Positive feedback amplifies a change to a rapid end point — e.g. childbirth, blood clotting.
  • A control loop has a receptor (sensor), a control centre, and an effector.

Cardiovascular System

  • Pathway: body → right atrium → right ventricle → lungs → left atrium → left ventricle → body.
  • The SA node is the natural pacemaker; it sets the heart rate.
  • Cardiac output = heart rate × stroke volume.
  • Blood pressure is written systolic/diastolic; a typical resting value is about 120/80 mmHg.

Respiratory System

  • Gas exchange occurs across the alveoli by simple diffusion: O2 in, CO2 out.
  • Oxygen is carried mainly bound to haemoglobin in red blood cells.
  • Breathing rate is driven chiefly by CO2 (and pH) levels detected by chemoreceptors, not oxygen.

Nervous and Endocrine Control

  • The neuron transmits electrical impulses; the synapse passes signals chemically via neurotransmitters.
  • Nervous control is fast and short-lived; endocrine (hormonal) control is slower but longer-lasting.
  • Insulin lowers blood glucose and glucagon raises it — a classic negative-feedback pair from the pancreas.

Renal and Digestive Systems

  • The nephron is the functional unit of the kidney; urine forms by filtration, reabsorption and secretion.
  • The kidney regulates water, electrolytes, pH and blood pressure and removes nitrogenous waste (urea).
  • Digestion breaks food into absorbable units; most absorption occurs in the small intestine.

Key Terms

Homeostasis
The maintenance of a stable internal environment (temperature, pH, glucose, etc.) around a set point.
Negative feedback
A control mechanism that opposes a change and returns a variable toward its set point; the dominant mode in physiology.
Cardiac output
The volume of blood pumped by the heart per minute; heart rate multiplied by stroke volume.
Nephron
The microscopic filtering unit of the kidney where urine is formed.

Practice Quiz — 8 Questions

correct out of 8

  1. The maintenance of a stable internal environment is called:

    • A.Metabolism
    • B.Homeostasis
    • C.Diffusion
    • D.Respiration
    B. Homeostasis — Homeostasis keeps variables such as temperature and glucose near a set point.

  2. Which type of feedback is most common in the body?

    • A.Positive feedback
    • B.Negative feedback
    • C.Feed-forward
    • D.No feedback
    B. Negative feedback — Negative feedback opposes change and restores the set point.

  3. The natural pacemaker of the heart is the:

    • A.AV node
    • B.SA node
    • C.Bundle of His
    • D.Purkinje fibres
    B. SA node — The sino-atrial (SA) node initiates each heartbeat.

  4. Cardiac output is calculated as:

    • A.Heart rate + stroke volume
    • B.Heart rate × stroke volume
    • C.Stroke volume ÷ heart rate
    • D.Blood pressure × heart rate
    B. Heart rate × stroke volume — Cardiac output = heart rate × stroke volume.

  5. In the lungs, gases are exchanged mainly by:

    • A.Active transport
    • B.Simple diffusion
    • C.Osmosis
    • D.Filtration
    B. Simple diffusion — O2 and CO2 move across the alveolar membrane by diffusion down their gradients.

  6. The main stimulus driving the rate of breathing is the level of:

    • A.Oxygen
    • B.Carbon dioxide
    • C.Glucose
    • D.Nitrogen
    B. Carbon dioxide — Chemoreceptors respond chiefly to CO2 and pH, not to oxygen.

  7. The functional unit of the kidney is the:

    • A.Alveolus
    • B.Nephron
    • C.Neuron
    • D.Villus
    B. Nephron — The nephron filters blood and forms urine.

  8. Which hormone lowers blood glucose?

    • A.Glucagon
    • B.Insulin
    • C.Adrenaline
    • D.Cortisol
    B. Insulin — Insulin lowers blood glucose; glucagon raises it.

References

  • Guyton & Hall, Textbook of Medical Physiology (standard reference)
  • Tortora & Derrickson, Principles of Anatomy and Physiology