BIOL 235 Midterm 1 Exam with correct answers
and rationale updated 2026
UNIT 1: INTRODUCTION TO ANATOMY AND PHYSIOLOGY
1. The science of body structures and the relationships among them is called:
A) Physiology
B) Anatomy
C) Histology
D) Embryology
Rationale: Anatomy is defined as the science of body structures and the relationships among them.
Physiology is the science of body functions -1.
2. Which level of structural organization is composed of atoms and molecules?
A) Cellular
B) Tissue
C) Chemical
D) Organ
Rationale: The chemical level includes atoms (smallest units of matter) and molecules (two or more
atoms joined together) -1.
3. The basic structural and functional units of an organism are:
A) Tissues
B) Cells
C) Organs
D) Molecules
Rationale: Cells are the basic structural and functional units of an organism, composed of
chemicals -1.
4. Groups of cells and the materials surrounding them that work together to perform a particular
function are called:
A) Organs
B) Systems
C) Tissues
D) Organelles
Rationale: Tissues are groups of cells and surrounding materials that work together for a particular
function -1.
5. Which of the following is NOT one of the main tissue types found in the human body?
A) Epithelial
B) Connective
,C) Myocardial
D) Nervous
Rationale: The four main tissue types are epithelial, connective, muscular, and nervous. Myocardial
is a specific type of muscle tissue, not a main category -4.
6. The correct sequence of levels of structural organization from simplest to most complex is:
A) Chemical → Tissue → Cellular → Organ → System → Organismal
B) Chemical → Cellular → Tissue → Organ → System → Organismal
C) Cellular → Chemical → Tissue → System → Organ → Organismal
D) Tissue → Cellular → Chemical → Organ → Organismal → System
Rationale: The six levels from smallest to largest are chemical, cellular, tissue, organ, system, and
organismal -6-18.
7. The sum of all chemical processes in the body is called:
A) Catabolism
B) Anabolism
C) Metabolism
D) Homeostasis
Rationale: Metabolism is the sum of all chemical processes in the body, including catabolism
(breakdown) and anabolism (building) -2.
8. The process by which unspecialized cells become specialized is called:
A) Reproduction
B) Growth
C) Differentiation
D) Metabolism
Rationale: Differentiation is the process by which unspecialized cells become specialized -2.
9. Which of the following is NOT a function of the integumentary system?
A) Protection from the external environment
B) Regulation of body temperature
C) Production of red blood cells
D) Vitamin D synthesis
Rationale: The integumentary system protects, regulates temperature, eliminates wastes, makes
vitamin D, and detects sensations. Red blood cell production occurs in the skeletal system (bone
marrow) -1.
10. The system that generates action potentials to regulate body activities is the:
A) Endocrine system
B) Nervous system
C) Muscular system
D) Cardiovascular system
Rationale: The nervous system generates action potentials (nerve impulses) to regulate body
activities, detects changes, and responds with muscular contractions or glandular secretions -1.
,11. Which system regulates body activities by releasing hormones?
A) Nervous system
B) Endocrine system
C) Lymphatic system
D) Respiratory system
Rationale: The endocrine system regulates body activities by releasing hormones transported in
blood to target organs -1.
12. The cardiovascular system includes all of the following EXCEPT:
A) Blood
B) Heart
C) Blood vessels
D) Lymph nodes
Rationale: The cardiovascular system consists of blood, heart, and blood vessels. Lymph nodes are
part of the lymphatic system -1.
13. Which system returns proteins and fluid to blood and carries lipids from the gastrointestinal
tract?
A) Cardiovascular system
B) Lymphatic and immunity system
C) Respiratory system
D) Endocrine system
Rationale: The lymphatic system returns proteins and fluid to blood and carries lipids from the GI
tract to blood -1.
14. The respiratory system helps regulate which of the following?
A) Blood glucose
B) Acid-base balance of body fluids
C) Body temperature
D) Red blood cell production
Rationale: The respiratory system transfers oxygen and carbon dioxide and helps regulate acid-base
balance of body fluids -1.
15. The tendency of the body to maintain a balanced or constant internal state is called:
A) Metabolism
B) Homeostasis
C) Differentiation
D) Reproduction
Rationale: Homeostasis is the tendency to maintain a balanced or constant internal state -18.
16. Fluid inside cells is called:
A) Extracellular fluid
B) Interstitial fluid
, C) Intracellular fluid
D) Plasma
Rationale: Intracellular fluid (ICF) is the fluid within cells; extracellular fluid (ECF) is outside cells -2-
18.
17. The fluid that bathes body cells and fills narrow spaces between cells of tissues is:
A) Plasma
B) Interstitial fluid
C) Intracellular fluid
D) Lymph
Rationale: Interstitial fluid is ECF that fills narrow spaces between cells of tissues -2-8.
18. Any disruption that changes a controlled condition is called:
A) A receptor
B) A stimulus
C) An effector
D) A response
Rationale: A stimulus is any disruption that changes a controlled condition -2.
19. In a feedback system, the structure that monitors changes and sends input is the:
A) Control center
B) Effector
C) Receptor
D) Stimulus
Rationale: The receptor monitors changes in a controlled condition and sends input to the control
center -2.
20. The pathway that flows toward the control center is called:
A) Efferent pathway
B) Afferent pathway
C) Motor pathway
D) Output pathway
Rationale: The afferent pathway carries input toward the control center; the efferent pathway
carries output away from it -2.
21. In a feedback system, the control center:
A) Detects the stimulus
B) Sets the range of values within which a controlled condition should be maintained
C) Produces the response
D) Receives the efferent signal
Rationale: The control center sets the range of values, evaluates input from receptors, and
generates output commands -2.
22. The structure that receives output from the control center and produces a response is the:
and rationale updated 2026
UNIT 1: INTRODUCTION TO ANATOMY AND PHYSIOLOGY
1. The science of body structures and the relationships among them is called:
A) Physiology
B) Anatomy
C) Histology
D) Embryology
Rationale: Anatomy is defined as the science of body structures and the relationships among them.
Physiology is the science of body functions -1.
2. Which level of structural organization is composed of atoms and molecules?
A) Cellular
B) Tissue
C) Chemical
D) Organ
Rationale: The chemical level includes atoms (smallest units of matter) and molecules (two or more
atoms joined together) -1.
3. The basic structural and functional units of an organism are:
A) Tissues
B) Cells
C) Organs
D) Molecules
Rationale: Cells are the basic structural and functional units of an organism, composed of
chemicals -1.
4. Groups of cells and the materials surrounding them that work together to perform a particular
function are called:
A) Organs
B) Systems
C) Tissues
D) Organelles
Rationale: Tissues are groups of cells and surrounding materials that work together for a particular
function -1.
5. Which of the following is NOT one of the main tissue types found in the human body?
A) Epithelial
B) Connective
,C) Myocardial
D) Nervous
Rationale: The four main tissue types are epithelial, connective, muscular, and nervous. Myocardial
is a specific type of muscle tissue, not a main category -4.
6. The correct sequence of levels of structural organization from simplest to most complex is:
A) Chemical → Tissue → Cellular → Organ → System → Organismal
B) Chemical → Cellular → Tissue → Organ → System → Organismal
C) Cellular → Chemical → Tissue → System → Organ → Organismal
D) Tissue → Cellular → Chemical → Organ → Organismal → System
Rationale: The six levels from smallest to largest are chemical, cellular, tissue, organ, system, and
organismal -6-18.
7. The sum of all chemical processes in the body is called:
A) Catabolism
B) Anabolism
C) Metabolism
D) Homeostasis
Rationale: Metabolism is the sum of all chemical processes in the body, including catabolism
(breakdown) and anabolism (building) -2.
8. The process by which unspecialized cells become specialized is called:
A) Reproduction
B) Growth
C) Differentiation
D) Metabolism
Rationale: Differentiation is the process by which unspecialized cells become specialized -2.
9. Which of the following is NOT a function of the integumentary system?
A) Protection from the external environment
B) Regulation of body temperature
C) Production of red blood cells
D) Vitamin D synthesis
Rationale: The integumentary system protects, regulates temperature, eliminates wastes, makes
vitamin D, and detects sensations. Red blood cell production occurs in the skeletal system (bone
marrow) -1.
10. The system that generates action potentials to regulate body activities is the:
A) Endocrine system
B) Nervous system
C) Muscular system
D) Cardiovascular system
Rationale: The nervous system generates action potentials (nerve impulses) to regulate body
activities, detects changes, and responds with muscular contractions or glandular secretions -1.
,11. Which system regulates body activities by releasing hormones?
A) Nervous system
B) Endocrine system
C) Lymphatic system
D) Respiratory system
Rationale: The endocrine system regulates body activities by releasing hormones transported in
blood to target organs -1.
12. The cardiovascular system includes all of the following EXCEPT:
A) Blood
B) Heart
C) Blood vessels
D) Lymph nodes
Rationale: The cardiovascular system consists of blood, heart, and blood vessels. Lymph nodes are
part of the lymphatic system -1.
13. Which system returns proteins and fluid to blood and carries lipids from the gastrointestinal
tract?
A) Cardiovascular system
B) Lymphatic and immunity system
C) Respiratory system
D) Endocrine system
Rationale: The lymphatic system returns proteins and fluid to blood and carries lipids from the GI
tract to blood -1.
14. The respiratory system helps regulate which of the following?
A) Blood glucose
B) Acid-base balance of body fluids
C) Body temperature
D) Red blood cell production
Rationale: The respiratory system transfers oxygen and carbon dioxide and helps regulate acid-base
balance of body fluids -1.
15. The tendency of the body to maintain a balanced or constant internal state is called:
A) Metabolism
B) Homeostasis
C) Differentiation
D) Reproduction
Rationale: Homeostasis is the tendency to maintain a balanced or constant internal state -18.
16. Fluid inside cells is called:
A) Extracellular fluid
B) Interstitial fluid
, C) Intracellular fluid
D) Plasma
Rationale: Intracellular fluid (ICF) is the fluid within cells; extracellular fluid (ECF) is outside cells -2-
18.
17. The fluid that bathes body cells and fills narrow spaces between cells of tissues is:
A) Plasma
B) Interstitial fluid
C) Intracellular fluid
D) Lymph
Rationale: Interstitial fluid is ECF that fills narrow spaces between cells of tissues -2-8.
18. Any disruption that changes a controlled condition is called:
A) A receptor
B) A stimulus
C) An effector
D) A response
Rationale: A stimulus is any disruption that changes a controlled condition -2.
19. In a feedback system, the structure that monitors changes and sends input is the:
A) Control center
B) Effector
C) Receptor
D) Stimulus
Rationale: The receptor monitors changes in a controlled condition and sends input to the control
center -2.
20. The pathway that flows toward the control center is called:
A) Efferent pathway
B) Afferent pathway
C) Motor pathway
D) Output pathway
Rationale: The afferent pathway carries input toward the control center; the efferent pathway
carries output away from it -2.
21. In a feedback system, the control center:
A) Detects the stimulus
B) Sets the range of values within which a controlled condition should be maintained
C) Produces the response
D) Receives the efferent signal
Rationale: The control center sets the range of values, evaluates input from receptors, and
generates output commands -2.
22. The structure that receives output from the control center and produces a response is the:
