Human Physiology
Welcome
Human Physiology I
Instructor: Isaac Boateng - 2025
Learning Objectives
Introduction to Human Physiology
General Physiology
Definition and scope of physiology
Levels of organization in the human body:
Cells
Tissues
Organs
Systems
Body Water
Total Body Water (TBW)
Body Fluid Compartments
Functions of Water
Measurement of body fluid compartments
Cellular Membranes
Structure
Membrane Transport
Diffusion
Simple diffusion
Ionic diffusion
Facilitated diffusion
Active Transport
Primary active transport
Secondary active transport
Vesicular Transport
Endocytosis
Exocytosis
Osmosis
Filtration
Homeostasis
Homeostatic Control Systems
Components of a Control System
Strategies for Maintenance of Homeostasis
Signal Transduction
Excitable Tissues
Nerve Cells
Types and classification
Resting Membrane Potential
Action Potential
Generation
Propagation
Properties
Muscle Tissue
Classification
Skeletal
Smooth
Cardiac
Structure
Excitation-Contraction Coupling
Relaxation
Communication Between Cells
Types of Synapses
EPSP
IPSP
Synaptic Integration
Neurotransmitters
Neuromuscular Transmission
Neuromuscular Blockers
Neuroeffector Junctions
Cholinergic Mechanism
Adrenergic Mechanism
Denervation Hypersensitivity
Systemic Physiology
Cardiovascular System
Respiratory System
Neuro-endocrine System
Reproductive System
Male and Female
Musculoskeletal System
Gastrointestinal System (GIT)
Urinary System
Recommended Books
Review of Medical Physiology - Ganong
Textbook of Medical Physiology - Guyton & Hall
Physiology - Berne et al
Human Physiology - Sherwood
Human Physiology - Vander et al
Principles of Physiology - Berne and Levy
Physiology - Constanzo
BRS Physiology
Seeley’s Anatomy and Physiology
Expectations
Class Format:
Lectures
Discussions
Case studies or interactive sessions
Assessment & Grading:
Exams (End of Sem & IAs)
Quizzes
Participation
Assignments
Student Responsibilities:
Attendance
Participation
Reading requirements
Why Physiology?
Scenario 1:
A 19-year-old first-year student collapses in a crowded, warm auditorium.
Symptoms: Dizziness, lightheadedness, nausea; confusion upon regaining consciousness.
Scenario 2:
A 23-year-old nursing intern experiences weakness and confusion after skipping meals during a long shift.
Introduction to Human Physiology
Definition: Scientific investigation of processes/functions of living things.
Major Goals:
Understanding and predicting body's responses to stimuli
Understanding homeostasis maintenance within a changing environment
Physiology Prefixes
Homeo-: Similar, constant (Homeostasis)
Hyper-: Excessive (Hypertension)
Hypo-: Deficient (Hypoglycemia)
Iso-: Equal (Isotonic)
Auto-: Self (Autoregulation)
Neuro-: Nerve (Neurotransmitter)
Electro-: Electric charge (Electrolyte)
Angio-: Vessel (Angiogenesis)
Brady-: Slow (Bradycardia)
Tachy-: Fast (Tachycardia)
Hemo-/Hema-: Blood (Hemodynamics)
Vaso-: Vessel (Vasodilation)
Myo-: Muscle (Myocardium)
Sarc-: Flesh, muscle (Sarcoplasm)
The Physiological Society
Organization of Physiology Levels:
Cell Physiology: Processes in cells
Systemic Physiology: Functions of organ systems
Neurophysiology: Nervous system
Cardiovascular Physiology: Heart and blood vessels
Exercise Physiology: Changes due to exercise
Pathophysiology: Disease aspects and changes from disease
Level of Organization of the Human Body
Chemical Level: Atoms combine to form molecules
Cell Level: Molecules form organelles, making up cells
Tissue Level: Similar cells and materials form tissues
Organ Level: Different tissues combine to form organs
Organ System Level: Organs coordinate for a major physiological function
Organismal Level: Organ systems make up an organism
Cellular Level
The Cell: Basic structural and functional unit of life
Cell Specialization: Types of cells and their roles (e.g., neurons, myocytes)
Physiological Processes:
Membrane transport
Cellular respiration
Signal transduction
Muscle Cells
Nerve Cell (Neuron)
Components: Axon, axon terminals, dendrites, nucleus, cell body
Tissue Level
Definition: Group of similar cells performing a specific function
Four Basic Types:
Epithelial (e.g., skin, lining of organs)
Connective (e.g., bone, blood)
Muscle (e.g., cardiac, skeletal)
Nervous (e.g., brain, spinal cord)
Organ Level
Definition: Two or more tissues working together for specific functions
Examples:
Heart: Pumps blood (muscle + connective + nervous tissues)
Lungs: Gas exchange (epithelial + connective tissues)
Organ System Level
Definition: Groups of organs coordinating for a major physiological function
Examples:
Cardiovascular System: Heart, blood vessels
Digestive System: Stomach, intestines, liver
Organismal Level
Definition: Whole human body as a functional unit
Integration: Systems work together for homeostasis
Body Water
Importance: Major chemical component and essential medium for internal environment
TBW Variations:
Decreases with age
Percentages by gender and body fat
Daily Fluid Intake and Output
Water Intake:
Ingestion: Drinking, eating, metabolism
Water Output:
Insensible losses, sweating, urine, feces
Body Fluid Compartments
Distribution:
Intracellular Fluid (ICF):
Comprises 2/3 TBW, high in potassium
Extracellular Fluid (ECF):
Comprises 1/3 TBW, high in sodium
Subcompartments: Interstitial Fluid, Plasma, Transcellular Fluid
Functions of H2O
Vital functions including: transport, metabolism, organ protection, temperature regulation, detoxification, and more.
Cellular Membranes
Definition: Semipermeable lipid bilayer enclosing cell contents
Structure: Thin, pliable, elastic; composed of lipids, proteins, carbohydrates
Lipids
Major Classes:
Phospholipids
Cholesterol
Glycolipids
Membrane Proteins
Types: Integral (transmembrane and monotopic) and Peripheral proteins
Carbohydrates
Role: About 3% of plasma membrane weight, including glycolipids and glycoproteins
Membrane Transport
Definition: Mechanisms regulating movement of solutes across membranes
Types of Transport: Diffusion (simple and facilitated) and Active Transport (primary and secondary)
Active Transport
Primary Active Transport: Uses ATP (e.g., Na+-K+ pump)
Secondary Active Transport: Couples ion movement with solute transport (e.g., Na+ and glucose)
Vesicular Transport
Definition: Movement of macromolecules in vesicles
Types: Endocytosis (phagocytosis, pinocytosis, receptor-mediated) and Exocytosis
Osmosis
Definition: Passive diffusion of water across a semipermeable membrane
Filtration
Definition: Fluid forced through a membrane due to pressure differences.
Possible Questions from Human Physiology I Notes
Introduction to Human Physiology
What is the definition of human physiology?
What are the major goals of studying physiology?
Levels of Organization in the Human Body
What are the different levels of organization in the human body?
How do cells, tissues, organs, and systems relate to each other?
Body Water
What is Total Body Water (TBW) and why is it important?
How does TBW vary with age and body composition?
What are the functions of water in the body?
Cellular Membranes
What is the structure of a cellular membrane?
What are the different types of membrane transport?
Homeostasis
What is homeostasis and why is it important in physiology?
What are the components of a homeostatic control system?
What strategies are used for the maintenance of homeostasis?
Excitable Tissues
What are the main types of excitable tissues in the body?
How do nerve cells generate and propagate action potentials?
What are the classification types of muscle tissue?
Communication Between Cells
What are the different types of synapses?
How do neurotransmitters function in neuromuscular transmission?
What is denervation hypersensitivity?
Systemic Physiology
What are the major systems of the human body covered in physiology?
How do these systems interact to maintain homeostasis?
Physiological Processes
What are the main physiological processes occurring at the cellular level?
Physiology Prefixes
What do the prefixes homeo-, hyper-, hypo-, iso-, auto-, neuro-, electrolyte, vaso-, myo-, sarc- refer to in physiology?
Levels of Organization in Detail
What defines each level of organization from chemical to organismal?
What role does cell specialization play in physiology?
Body Fluid Compartments
What are the different body fluid compartments and their characteristics?
Membrane Transport Mechanisms
What are the differences between active transport and passive transport?
How does the Na+-K+ pump function in primary active transport?
Osmosis and Filtration
What is osmosis, and how does it differ from filtration?
Human physiology is the scientific investigation of processes/functions of living things.
Major goals include understanding and predicting the body's responses to stimuli and maintaining homeostasis within a changing environment.
The different levels of organization are: Chemical, Cell, Tissue, Organ, Organ System, Organismal.
Cells make up tissues, tissues make up organs, organs work together as systems to create a functioning organism.
Total Body Water (TBW) is the sum of all water in the body; it is important as it affects physiological processes.
TBW decreases with age; it varies by gender and body fat percentage.
Functions of water include transport, metabolism, organ protection, temperature regulation, and detoxification.
Cell membranes are semi-permeable lipid bilayers enclosing cell contents; they consist of lipids, proteins, and carbohydrates.
Types of membrane transport include passive transport (diffusion, facilitated diffusion) and active transport (primary and secondary).
Homeostasis is the maintenance of a stable internal environment; it is essential for survival and function.
Components of a homeostatic control system include a sensor, integrator, and effector.
Strategies for maintenance of homeostasis involve feedback mechanisms and physiological adjustments.
Major types of excitable tissues are nerve cells and muscle cells.
Nerve cells generate action potentials through depolarization and propagate them via axonal conduction.
Muscle tissue classification includes skeletal, smooth, and cardiac muscle.
Types of synapses are chemical and electrical synapses.
Neurotransmitters are chemical messengers released from nerve endings; they facilitate neuromuscular transmission by binding to receptors.
Denervation hypersensitivity is increased sensitivity of target tissues due to loss of innervation.
Major systems covered include cardiovascular, respiratory, neuro-endocrine, reproductive, musculoskeletal, gastrointestinal, and urinary systems.
These systems interact through complex networks to maintain homeostasis.
Main physiological processes at the cellular level include membrane transport, cellular respiration, and signal transduction.
Prefixes: Homeo- means similar; Hyper- means excessive; Hypo- means deficient; Iso- means equal; Auto- means self; Neuro- refers to nerves; Electro- refers to electric charges; Angio- refers to vessels; Brady- means slow; Tachy- means fast; Hemo-/Hema- refers to blood; Vaso- refers to vessels; Myo- refers to muscle; Sarc- refers to flesh or muscle.
Each organization level—from chemical to organismal—defines the complexity of life; higher levels integrate functions from lower levels.
Cell specialization refers to the unique functions and roles that different types of cells fulfill within the body.
Body fluid compartments include: Intracellular Fluid (ICF)—high in potassium; Extracellular Fluid (ECF)—high in sodium, includes interstitial fluid, plasma, and transcellular fluid.
Active transport requires energy (e.g., Na+-K+ pump) while passive transport does not; they differ in energy requirements and mechanisms of solute movement.
Osmosis is the passive diffusion of water across a semipermeable membrane; filtration involves fluid movement through a membrane driven by pressure differences.