Human Anatomy and Physiology: NMAT Biology Review
Introduction to Human Anatomy and Physiology
Human Anatomy and Physiology is a core component of the NMAT Biology section, focusing on the structure (anatomy) and function (physiology) of the human body. Understanding how organ systems are organized and how they work together to maintain homeostasis is essential for answering NMAT questions accurately. Rather than memorizing isolated facts, NMAT emphasizes functional relationships, cause-and-effect mechanisms, and system-level integration. This review covers the major human body systems, their structures, functions, and key physiological principles commonly tested in the NMAT.
Levels of Organization in the Human Body
The human body is organized into hierarchical levels:
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Chemical level: atoms and molecules such as water, proteins, lipids, and nucleic acids
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Cellular level: cells as the basic unit of life
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Tissue level: groups of similar cells performing a common function
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Organ level: structures composed of multiple tissues
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Organ system level: groups of organs working together
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Organism level: the complete human body
NMAT questions often test how disruptions at one level affect higher levels, such as how cellular dysfunction can impair organ system function.
Homeostasis and Feedback Mechanisms
Homeostasis refers to the body’s ability to maintain a stable internal environment despite external changes. Key variables regulated include temperature, blood glucose, pH, blood pressure, and oxygen levels.
Most homeostatic regulation occurs through negative feedback mechanisms, where a change in a variable triggers responses that reverse the deviation. For example, increased blood glucose stimulates insulin release, lowering glucose levels. Positive feedback, which amplifies changes, is less common and occurs in specific situations such as blood clotting and childbirth.
Understanding feedback loops is crucial for NMAT, especially when analyzing hormone regulation and nervous system responses.
Nervous System: Structure and Function
The nervous system provides rapid communication and coordination. It is divided into:
The PNS is further divided into the somatic nervous system (voluntary control) and the autonomic nervous system (involuntary control), which includes the sympathetic and parasympathetic divisions.
Neurons transmit signals via electrical impulses called action potentials and chemical neurotransmitters at synapses. NMAT questions commonly focus on neuron structure, impulse transmission, and differences between sympathetic (“fight or flight”) and parasympathetic (“rest and digest”) responses.
Endocrine System and Hormonal Regulation
The endocrine system regulates body functions through hormones released into the bloodstream. Major endocrine glands include the pituitary, thyroid, adrenal glands, pancreas, and gonads.
Hormones can be classified as peptide, steroid, or amino acid–derived hormones. Their effects depend on target cell receptors, not just hormone concentration. For example, insulin lowers blood glucose by promoting cellular uptake, while glucagon increases blood glucose by stimulating glycogen breakdown.
The hypothalamus-pituitary axis is frequently tested in NMAT due to its central role in hormonal control and feedback regulation.
Circulatory System and Blood Physiology
The circulatory system transports oxygen, nutrients, hormones, and wastes. It consists of the heart, blood vessels, and blood.
The heart functions as a muscular pump with four chambers: two atria and two ventricles. Blood flow follows a specific pathway through pulmonary and systemic circulation. Understanding blood flow direction and valve function is essential for NMAT questions.
Blood is composed of plasma, red blood cells, white blood cells, and platelets. Red blood cells transport oxygen using hemoglobin, while white blood cells play key roles in immunity. NMAT often tests oxygen transport, blood pressure regulation, and the relationship between structure and function in blood vessels.
Respiratory System and Gas Exchange
The respiratory system enables gas exchange between the body and the environment. Major structures include the nasal cavity, trachea, bronchi, bronchioles, and alveoli.
Gas exchange occurs in the alveoli through diffusion, driven by partial pressure gradients. Oxygen binds to hemoglobin in red blood cells, while carbon dioxide is transported primarily as bicarbonate ions.
NMAT questions frequently focus on breathing mechanisms, gas transport, and how respiratory and circulatory systems work together to supply oxygen to tissues.
Digestive System and Nutrient Absorption
The digestive system breaks down food into absorbable nutrients. It includes the mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas, and gallbladder.
Digestion involves both mechanical and chemical processes. Enzymes play a key role in breaking down carbohydrates, proteins, and lipids. Most nutrient absorption occurs in the small intestine, particularly in the jejunum and ileum, through structures called villi and microvilli.
Understanding enzyme specificity, nutrient absorption pathways, and the role of accessory organs is important for NMAT biology questions.
Urinary System and Osmoregulation
The urinary system maintains fluid balance, electrolyte levels, and waste elimination. It includes the kidneys, ureters, bladder, and urethra.
The functional unit of the kidney is the nephron, which filters blood, reabsorbs essential substances, and secretes wastes. Key processes include filtration, reabsorption, and secretion.
NMAT commonly tests nephron structure, urine formation, and hormonal regulation of kidney function, particularly the roles of antidiuretic hormone (ADH) and aldosterone.
Muscular System and Movement
The muscular system allows movement, posture, and heat production. There are three types of muscle tissue: skeletal, smooth, and cardiac.
Skeletal muscles contract through the sliding filament mechanism involving actin and myosin. Muscle contraction is regulated by calcium ions and ATP. Understanding neuromuscular junctions and muscle fiber types is essential for NMAT questions related to movement and energy use.
Skeletal System and Support
The skeletal system provides structural support, protection, and sites for muscle attachment. It also plays a role in mineral storage and blood cell formation.
Bones are classified as long, short, flat, or irregular. Bone tissue undergoes continuous remodeling through the actions of osteoblasts and osteoclasts. NMAT may test bone structure, joint types, and the physiological role of calcium and phosphorus.
Immune System and Defense Mechanisms
The immune system protects the body from pathogens. It includes innate defenses such as skin, inflammation, and phagocytic cells, as well as adaptive immunity involving lymphocytes.
B cells produce antibodies, while T cells mediate cellular immunity. Understanding antigen-antibody interactions and immune memory is important for NMAT biology, especially in questions related to infection and vaccination.
Reproductive System and Human Development
The reproductive system enables sexual reproduction. Male and female reproductive organs produce gametes and sex hormones.
Fertilization results in a zygote, which undergoes cell division and differentiation during development. NMAT questions often focus on hormone regulation, gametogenesis, and basic stages of human development.
Integration of Body Systems
Human physiology emphasizes the integration of systems rather than isolated functions. For example, exercise involves coordination among muscular, respiratory, circulatory, and nervous systems. Hormones and neural signals work together to regulate body responses.
NMAT questions frequently test this integrative understanding, requiring students to analyze how changes in one system affect others.
NMAT Study Tips for Anatomy and Physiology
To prepare effectively for NMAT:
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Focus on functional relationships rather than memorization
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Understand feedback mechanisms and regulatory pathways
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Practice interpreting diagrams and physiological scenarios
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Connect structure to function across organ systems
A solid conceptual understanding of human anatomy and physiology will significantly improve performance in the NMAT Biology section.
Conclusion
Human Anatomy and Physiology is a foundational topic for NMAT Biology, emphasizing structure-function relationships, homeostasis, and system integration. By mastering the major organ systems and their physiological mechanisms, NMAT examinees can confidently tackle both conceptual and application-based questions. Consistent review, diagram analysis, and practice questions are key to achieving a high NMAT Biology score.
Problem Set: Human Anatomy and Physiology (NMAT Level)
Questions 1–10: General Physiology and Homeostasis
Q1. Which of the following best describes homeostasis?
A. Maintenance of constant external conditions
B. Regulation of internal conditions within narrow limits
C. Elimination of all environmental changes
D. Continuous increase in metabolic rate
Q2. A rise in blood glucose levels after a meal triggers insulin release. This is an example of:
A. Positive feedback
B. Neural regulation
C. Negative feedback
D. Feedforward control
Q3. Which variable is most directly regulated by the respiratory system?
A. Blood glucose
B. Blood pH
C. Blood calcium
D. Body temperature
Q4. Failure of a negative feedback mechanism would most likely result in:
A. Faster response time
B. Stable internal environment
C. Uncontrolled deviation from normal values
D. Increased positive feedback
Q5. Which organ system is primarily responsible for short-term regulation of homeostasis?
A. Endocrine system
B. Nervous system
C. Immune system
D. Digestive system
Q6. Which statement about positive feedback is correct?
A. It maintains equilibrium
B. It reverses initial changes
C. It amplifies the initial stimulus
D. It occurs in most physiological processes
Q7. During fever, body temperature rises above normal. This suggests that:
A. Homeostasis is permanently lost
B. Feedback mechanisms are inactive
C. Set point has been temporarily altered
D. Positive feedback dominates all systems
Q8. Which structure acts as the main control center for homeostasis?
A. Pituitary gland
B. Hypothalamus
C. Medulla oblongata
D. Cerebellum
Q9. Blood pressure regulation involves which two major systems working together?
A. Digestive and urinary
B. Nervous and endocrine
C. Skeletal and muscular
D. Immune and lymphatic
Q10. Which condition would most directly disrupt homeostasis?
A. Increased oxygen intake
B. Stable hormone secretion
C. Failure of kidneys to regulate electrolytes
D. Balanced diet
Questions 11–20: Nervous and Endocrine Systems
Q11. Which part of the neuron receives incoming signals?
A. Axon
B. Synaptic cleft
C. Dendrites
D. Myelin sheath
Q12. The sympathetic nervous system is most active during:
A. Sleep
B. Digestion
C. Stress or danger
D. Relaxation
Q13. Neurotransmitters are released at the:
A. Axon hillock
B. Nodes of Ranvier
C. Synapse
D. Dendrite
Q14. Which hormone is released by the pancreas to lower blood glucose?
A. Glucagon
B. Cortisol
C. Insulin
D. Epinephrine
Q15. Steroid hormones differ from peptide hormones because they:
A. Act faster
B. Bind to membrane receptors
C. Enter target cells and bind intracellular receptors
D. Are water-soluble
Q16. The pituitary gland is often called the “master gland” because it:
A. Produces the most hormones
B. Controls growth directly
C. Regulates other endocrine glands
D. Is independent of the hypothalamus
Q17. Which hormone increases metabolic rate?
A. Insulin
B. Thyroxine
C. Aldosterone
D. ADH
Q18. Hormones exert effects only on target cells that:
A. Are nearby
B. Are electrically excitable
C. Have specific receptors
D. Are metabolically active
Q19. Which endocrine response is regulated by negative feedback?
A. Blood clotting
B. Oxytocin release during labor
C. Thyroid hormone secretion
D. Action potential generation
Q20. Damage to the hypothalamus would most directly affect:
A. Muscle contraction
B. Hormone regulation and temperature control
C. Blood filtration
D. Oxygen transport
Questions 21–30: Circulatory, Respiratory, and Excretory Systems
Q21. The primary function of red blood cells is to:
A. Fight infection
B. Transport oxygen
C. Clot blood
D. Regulate temperature
Q22. Oxygen binds to which molecule in red blood cells?
A. Myoglobin
B. Hemocyanin
C. Hemoglobin
D. Albumin
Q23. Gas exchange in the lungs occurs primarily in the:
A. Bronchi
B. Trachea
C. Alveoli
D. Diaphragm
Q24. Carbon dioxide is transported in the blood mainly as:
A. Dissolved gas
B. Carbonic acid
C. Bicarbonate ions
D. Carbaminohemoglobin
Q25. Which structure prevents backflow of blood in the heart?
A. Arteries
B. Veins
C. Valves
D. Capillaries
Q26. The functional unit of the kidney is the:
A. Nephron
B. Glomerulus
C. Loop of Henle
D. Renal pelvis
Q27. Filtration of blood occurs primarily in the:
A. Proximal tubule
B. Distal tubule
C. Glomerulus
D. Collecting duct
Q28. ADH increases water reabsorption by acting on the:
A. Glomerulus
B. Loop of Henle
C. Collecting duct
D. Renal artery
Q29. Increased breathing rate during exercise helps maintain:
A. Blood glucose
B. Blood pH
C. Electrolyte balance
D. Blood volume
Q30. Failure of the kidneys would most directly cause:
A. Reduced oxygen uptake
B. Loss of motor control
C. Accumulation of metabolic wastes
D. Decreased digestion
Answer Key
1. B
2. C
3. B
4. C
5. B
6. C
7. C
8. B
9. B
10. C
11. C
12. C
13. C
14. C
15. C
16. C
17. B
18. C
19. C
20. B
21. B
22. C
23. C
24. C
25. C
26. A
27. C
28. C
29. B
30. C
NMAT Study Guide: Complete Preparation Guide for Medical School in the Philippines
NMAT Biology Review: NMAT Study Guide
