Human Physiology - PSL223 Quiz

Course Information

• Course title and code: Human Physiology - PSL223
• Credit hours: 3 hours (2+1)
• Offered in: Public Health and Nursing
• Prerequisites:
  • 1st year (Basic Foundation course)
  • Biology course in first year II semester

Course Objectives

• Identify physiological terminology
• Understand human body structure (chemical, cellular, tissue, organ, system levels)
• Demonstrate understanding of homeostasis mechanisms
• Plan, perform, and interpret physiological functions
• Explain pathophysiological bases of common diseases

Course Assessment

• Quiz (MCQs): 5% (any week before 1st midterm)
• 1st Midterm Theory Exam (MCQs): 15% (7th week)
• 1st Midterm Theory Exam (Spotting, True/False, Fill in the blanks): 15% (8th week)
• 2nd Midterm Theory Exam (MCQs): 15% (11th week)
• Assignment: 10% (12th week)
• Final Practical Exam (Spotting, True/False, Fill in the blanks): 15% (after 15th week)
• Final Theory Exam (MCQs, TF, Fill in the blanks, essay): 25% (after 15th week)

Learning Resources

• Ross and Wilson's "Anatomy and Physiology in Health and Illness" 12th Edition; ISBN 978-0-7020-5325-2, International ISBN 978-0-7020-5326-9. (Pages 4-7)
• Arthur C. Guyton, update, Textbook of Medical Physiology, W.B. Saunders Company. 2010.
• List of Essential References Materials (Journals, Reports, etc.):
  • John B., Respiratory physiology, The William & Wilkins Company
  • Cecil Gray John Nunn and J.E. Uttering, General Anesthesia, Butterwirths (pages 32-45)

What is Physiology?

• The scientific study of normal functions of living organisms

Branches of Physiology

• Human physiology
• Cellular physiology
• Cardiovascular physiology
• Renal physiology
• Respiratory physiology
• Gastrointestinal physiology
• Neurophysiology
• Muscular physiology
• Endocrine physiology

Levels of Organization of the Body

• Chemical
• Cellular
• Tissue
• Organ
• System
• Human

Organ Systems

• Lists organ systems with their roles
  • Endocrine
  • Nervous
  • Musculoskeletal
  • Cardiovascular
  • Respiratory
  • Urinary
  • Gastrointestinal
  • Reproduction
  • Immune
  • Integumentary

Organization of the Body: The Cell

• Cell: The smallest structural and functional unit of living organisms
• Cytology: The science of cells as fundamental units of living things

Organization of the Body: The Cell - Plasma Membrane

• Outer boundary that separates intracellular from external environment
• Selective barrier for passage of substances
• Role in cellular communication

Functions of Membrane Proteins

• Ion channels
• Transporters (Carrier proteins): transport molecules through the membrane
• Receptors: cellular recognition (ligand binds)
• Enzymes: catalyze chemical reactions
• Cell Identity markers

Cytoplasm - Components

• Cytosol: Fluid portion (mostly water) in the cell
• Organelles: Subcellular structures with specific functions

Organelles: Nucleus

• Spherical/oval structure (usually prominent)
• Nuclear envelope: double membrane separating nucleus from cytoplasm
• Nuclear pores: control movement between nucleus and cytoplasm
• Nucleolus: produces ribosomoes
• Chromosomes: contain hereditary units (genes)

Organelles: Mitochondria

• Known as "powerhouses" of the cell
• Double membrane (inner and outer mitochondrial membranes)
• Cristae: folds of inner membrane
• Matrix: central fluid-filled cavity
• Responsible for ATP generation through cellular respiration

Organelles: Ribosomes

• Sites for protein synthesis
• Tiny granules composed of RNA and protein
• Synthesize proteins from amino acids

Organelles: Endoplasmic Reticulum

• Network of membranes (flattened sacs or tubules)
  • Rough ER: connected membrane system, studded with ribosomes, involved in protein synthesis
  • Smooth ER: a continuous network, not studded with ribosomes, synthesizes lipids and steroids

Organelles: Golgi Complex

• Sacs called cisternae
• Packages and processes proteins for transport to different destinations
• Proteins are transported in vesicles
• Important in cells that synthesize and export proteins

Organelles: Lysosomes

• Vesicles formed from Golgi complex
• Contain digestive enzymes
• Break down fragments of organelles and large molecules (e.g., RNA, DNA, carbohydrates, proteins)

Organelles: Cytoskeleton

• Extensive network of protein fibers
• Microfilaments: smallest fibers (e.g., actin in muscle cells)
• Microtubules: larger, maintain cell shape, involved in organelle and chromosome movement

Tissue

• Tissues: Group of cells similar in structure and function
• Histology: Branch of science that studies structure and functions of body tissues

Types of Tissues

• Epithelial (covers and lines body surfaces)
• Connective (supports and connects organs)
• Muscle (contraction and movement)
• Nervous (initiates and transmits nerve impulses)

Development of Tissues

• Tissues develop from three primary germ layers: Ectoderm, Endoderm, and Mesoderm

Epithelial Tissues

• Cells arranged in continuous sheets
• Covering and lining of body parts
• Classified by arrangement and cell shape (e.g., simple squamous, simple cuboidal, simple columnar, stratified squamous)
  • Major functions: Protection, secretion, absorption

Glandular Epithelium

• Formed from epithelium Categorized into:
  • Exocrine glands: produce secretion into ducts (e.g., sweat, oil, saliva)
  • Endocrine glands: produce hormones released into blood

Muscular Tissue

• Elongated cells (muscle fibers, myocytes)
• Classified into three types
  • Skeletal muscle
  • Cardiac muscle
  • Smooth muscle

Nervous Tissue

• Two types of cells are found in the nervous system:
  • Exitable cells (neurons): Initiate, conduct, receive, and transmit information
  • Non-excitable cells (glial cells): support neurons

Connective Tissue

• The most diverse tissue type
• Characterized by extracellular matrix
• Examples: Bone, Tendons, Fat, Blood

Body Fluid Compartments

• Internal environment: fluid surrounding cells (Extracellular Fluid - ECF)
• 70-kg man: Total body water (42 liters); with intracellular fluid (ICF) and extracellular fluid (28 L), with plasma (3 liters) and interstitial fluid (11 liters).

Homeostasis

• Ability to maintain relatively constant internal environment
• Conditions regulated include temperature, volume, composition
• Negative feedback loop (variable changes in one direction, causing a response to correct change).

Homeostasis: Terms

• Set point: The expected value of a regulated variable (e.g., body temperature, blood glucose level, blood pH)
• Error signal: Difference between the current value and the set point of the regulated variable, that triggers a reaction.
• Important homeostatic parameters which are controlled by negative feedback: Temperature, Volume, and Composition

Homeostasis: Components

• Receptors: detect changes in the environment (e.g., thermoreceptors, chemoreceptors, baroreceptors)
• Integrating centers: process information from receptors to effectors to maintain homeostatic balance (e.g., brain).
• Effectors: carry out actions that restore homeostasis (e.g., muscles and glands)
• Signals: Allow components to communicate (e.g., chemical signals such as hormones, or nerve signals)

Homeostasis: Thermoregulation

• Mechanisms of heat transfer between the body and environment: Radiation, Conduction, Evaporation, Convection

Thermoregulation: Components

• Receptors: thermoreceptors (central and peripheral)
• Effectors: sweat glands, skeletal muscles, smooth muscles of vessels.
• Integrating center: thermoregulatory center in the hypothalamus.
• Signals: nerve impulses via neurons and chemicals via hormones

Thermoneutral Zone

• Range of outside temperatures where body temperature is regulated by blood flow alone (25-30°C)

Fever

• Rise in core body temperature that accompanies infection
• White blood cells secrete pyrogens; resulting in body temperature set point increase
• Enhanced immune response