ER

Lecture 1: Introduction to the study of anatomy and physiology (EPBIOL259)

L1.1 Anatomy

  • Anatomy and Physiology are highly interdependent and complementary.
  • Anatomy: study of the internal and external structure(s) of the human body.
    • Greek origin: “to cut apart.”
    • Sub-classes:
    • Gross (macroscopic) anatomy
    • Microscopic anatomy
    • Surface anatomy
    • Systemic anatomy
    • Regional anatomy
  • Physiology: study of the dynamic functions and vital processes of the human body.
    • Subdisciplines include:
    • Neurophysiology
    • Pathophysiology (mechanisms of disease)
  • Pathology: science/study of causes and effects of diseases.

L1.1 The Study of Anatomy: Subclasses

  • Gross anatomy: using surface observation or dissection to study structures visible to the naked eye; macroscopic.
  • Histology: tissue specimens thinly sliced, stained, observed under a microscope.
  • Histopathology: microscopic examination of tissues for disease.
  • Surface anatomy: external structure of the body; important in conducting physical examinations; macroscopic.
  • Systemic anatomy: study of one organ system at a time; approach used in this course.
  • Regional anatomy: study of multiple organ systems in a specific region of the body.
  • Comparative anatomy: comparison of more than one species to study generalizations and evolutionary trends (e.g., human vs. chimpanzee).

L1.1 Methods of examination of the human body

  • Inspection: simplest method of examining the body.
  • Dissection: cutting and separating tissues to reveal relationships; crucial for accurately mapping anatomy.
  • Palpation: feeling structures with fingertips (e.g., palpating swollen lymph nodes, taking pulse).
  • Auscultation: listening to sounds made by the body (e.g., heart and lung sounds).
  • Percussion: tapping on the body to detect signs of abnormalities (e.g., fluid or air pockets).
  • Medical imaging: viewing inside the body without surgery (e.g., radiology).

L1.1 Anatomical variation

  • Internal anatomy varies between individuals.
  • Textbooks teach the most common patterns; some individuals may lack certain organs or have organs in different positions.
  • Examples:
    • Some people may have two spleens, one kidney, or no uterus.
  • Figure reference: variations in human anatomy (e.g., pelvic kidney, horseshoe kidney, aorta variations).

L1.1 Anatomical position and planes

  • Anatomical position provides a frame of reference for examination and accuracy.
  • Anatomical position features:
    • Standing straight/upward
    • Face forward
    • Feet parallel
    • Arms at sides
    • Palms facing forward
  • Planes of reference (three major invisible planes):
    • Sagittal plane: divides body into left and right portions.
    • Frontal (coronal) plane: divides body into anterior (front) and posterior (back) portions.
    • Transverse (horizontal) plane: divides body into superior (upper) and inferior (lower) portions.
  • Subtypes within sagittal plane:
    • Median (midsagittal) plane: divides body into equal left and right halves along the midline.
    • Parasagittal plane: divides body into unequal left and right portions; parallel to the mid-sagittal plane.

L1.1 Anatomical planes (visual reference)

  • Sagittal plane: left-right divisions.
  • Frontal plane: anterior-posterior divisions.
  • Transverse plane: superior-inferior divisions.

L1.1 Learning Activity A

  • Questions:
    • What is the difference between gross anatomy and histology?
    • In a routine physical, how do palpation and auscultation differ?
    • What is the difference between anatomy and physiology?

L1.1 Major body regions

  • Major regional division concepts:
    • Axial region: everything but the limbs; includes head, neck, and trunk.
    • Trunk is subdivided into: thoracic region (above the diaphragm) and abdominal & pelvic regions (below the diaphragm).
    • Appendicular region: upper and lower extremities (limbs), including the shoulder girdle and pelvis.
  • External body regions: anterior/ventral view and posterior/dorsal view (Figure 1.10).
  • Internal regions: Quadrants of the abdomen (four quadrants) and the correlation with internal anatomy (Figure 1.9).

L1.1 Internal region: Quadrants of the abdomen

  • Four quadrants of the abdominopelvic region.
  • Correlation of internal anatomy with the four quadrants (Figure 1.9).

L1.1 Learning Activity C

  • Questions:
    • Do the following areas belong to the appendicular or axial region: thoracic, gluteal, patellar, scapula?

L1.1 Major body cavities and membranes

  • Large spaces housing and protecting organs include ventral, dorsal, and pericardial regions.
  • Dorsal cavity components:
    • Cranial cavity: enclosed by the skull; contains brain.
    • Vertebral canal: continuous with cranial cavity; space along the vertebral column.
    • Meninges: membranes lining both cranial and vertebral cavities; protect nervous tissue.
  • Ventral cavities: body cavities containing internal organs (viscera) lined by serous membranes.
    • Some cavities open to environment are lined by mucous membranes.
  • Major body cavities and membranes (designations may be diagrammed in Figure 1.11):
    • Thoracic cavity: separated from the abdominopelvic cavity by the diaphragm; contains mediastinum (esophagus, trachea, heart, major vessels); contains pericardium and pleura.
    • Abdominopelvic cavity: separated from thoracic by the diaphragm; subdivided into abdominal and pelvic cavities; abdominal contains most digestive organs; pelvic contains distal large intestine, bladder, urethra, reproductive organs.
  • Membranes:
    • Peritoneum: serous membrane lining the peritoneal cavity.
    • Peritoneal cavity: potential space between parietal and visceral peritoneum.
    • Parietal peritoneum: outer layer lining the abdominal wall.
    • Visceral peritoneum: covers abdominal viscera; mesentery suspends certain viscera from the body wall; serosa covers some surfaces of viscera.
    • Peritonitis: inflammation of the peritoneum.
  • Retroperitoneal vs intraperitoneal:
    • Retroperitoneal organs lie against the posterior body wall; covered by peritoneum only on the side facing the cavity (e.g., kidneys, aorta, IVC, pancreas).
    • Intraperitoneal organs are encircled by peritoneum and suspended by mesenteries (e.g., loops of small intestine).

L1.1 Learning Activity D

  • Prompt: Identify which major body cavity contains:
    • Spinal cord, heart, kidney, lung, gallbladder, thoracic vertebra.

L1.2 Physiology

  • Physiology: dynamic functions and vital processes in living bodies.
  • Subdisciplines of physiology include:
    • Neurophysiology: function of the nervous system.
    • Pathophysiology: mechanisms of disease.
    • Comparative physiology: how different species solve similar problems (e.g., reproduction, respiration).
  • Structural hierarchy of the human body (Levels of organization, from largest to smallest):
    • Organism → Organ systems → Organs → Tissues → Cells → Organelles → Molecules → Atoms.
  • Levels of human structure (detailed):
    • Organism: a single, complete individual.
    • Organ system (body systems): group of organs working together to carry out vital functions; there are 11 organ systems in humans.
    • Organ: composed of two or more tissue types that work together to perform a function (e.g., heart, kidneys).
    • Tissues: collection of similar cells and cell products that act together; four tissue types: epithelial, connective, nervous, muscular.
    • Cells: smallest structural and functional units of life; contain nucleus and organelles; building blocks of life.
    • Organelles: microscopic structures carrying out cell functions (e.g., mitochondria, lysosomes).
    • Molecules and Atoms: molecules are two or more atoms; atoms are the smallest unit of an element.

L1.2 Organ systems (overview)

  • The course mentions 11 organ systems with principal organs and functions; common examples include:
    • Integumentary, Skeletal, Muscular, Nervous, Endocrine, Cardiovascular, Lymphatic/Immune, Respiratory, Digestive, Urinary, Reproductive.
  • Organ systems are interrelated and often depend on one another for proper functioning.

L1.2 Essential life functions

  • All living organisms share essential life functions:
    • Organization: living things are more organized than nonliving; they expend energy to maintain order; breakdown of order leads to disease.
    • Cells: living things are compartmentalized into cells; smallest living units.
    • Metabolism: sum of all internal chemical changes; intake and chemical alteration of molecules; constant turnover of molecules in the body.
    • Growth: increase in size via metabolic change; mainly through synthesis of molecules from food.
    • Development: change in form or function over the lifetime; differentiation of cells and tissues.
    • Excitability: ability to sense and react to stimuli; occurs at all levels.
    • Homeostasis: ability to maintain a stable internal environment within set parameters despite external changes.
    • Reproduction: organisms can produce copies of themselves; genetic information passed to offspring.
    • Evolution: genetic changes in a population over time; some variations are favored by the environment; evolutionary medicine interprets disease in terms of species history.

L1.2 Homeostasis and feedback loops

  • Homeostasis: a dynamic state of equilibrium; maintained by neural and hormonal control systems.
  • Disturbances to homeostasis can lead to illness or death.
  • Pathophysiology: study of mechanisms of disease or unstable conditions when homeostatic controls go awry.

L1.2 Negative feedback and stability

  • Negative feedback maintains homeostasis by opposing the initial change; values stay within a narrow range around a set point.
  • It does not produce absolute constancy; fluctuations occur around the set point.
  • Example: Blood pressure regulation (BP):
    • When standing up, gravity lowers BP; baroreceptors near the heart detect drop and signal the cardiac control center in the brain.
    • The control center increases heart rate, raising BP back toward normal.
    • Negative feedback reduces the effects of the initial stimulus.
  • Components of homeostatic feedback loops:
    • Receptor (sensor): detects changes in the controlled condition (e.g., thermoreceptors detecting temperature changes).
    • Integrating control center: processes information and determines a response (e.g., cardiac control center in the brain).
    • Effector: carries out the response to restore homeostasis (e.g., organ, muscle, gland actions).
  • Communication between receptors, control centers, and effectors is critical for loop function.

L1.2 Positive feedback and rapid change

  • Positive feedback is a self-amplifying cycle: changes lead to greater changes in the same direction.
  • It is not generally a mechanism for maintaining homeostasis; it accelerates processes.
  • A classic example: childbirth
    • Fetus head pushes against cervix, stimulating nerve endings.
    • Nerve signals stimulate the pituitary to secrete oxytocin, which stimulates uterine contractions.
    • Contractions push the fetus further, increasing cervix stimulation and contraction intensity until birth.
  • Positive feedback can have a beneficial outcome in certain physiological processes (e.g., childbirth).

L1.2 Physiological variation

  • Physiology is more variable than anatomy.
  • Normal values are typically given for healthy young adults (e.g., resting metabolic rate, BMI).
  • Variability arises from factors such as: sex, age, weight, diet, physical activity, environment.

L1.2 Learning Activity E

  • Prompts:
    • What is the difference between growth and development?
    • Why is it likely that positive feedback can lead to loss of homeostasis, and how can negative feedback restore it?
    • Why is it better to define homeostasis as a dynamic equilibrium rather than a constant internal state?

L1.3 The Language of Medicine

  • Scientific and medical terminology is more manageable when broken into smaller parts.
  • Example: hyponatremia = hypo- (below normal) + natr- (sodium) + -emia (condition of the blood).

L1.3 Medical terminology

  • Word elements:
    • Word root / combining form: core meaning (e.g., cardi- = heart).
    • Prefix: at the beginning; modifies word (e.g., epigastric = above stomach).
    • Suffix: at the end; modifies word (e.g., microscope, microscopy, microscopic).

L1.3 Common prefixes (Table 1.2)

  • a- or an-: without
  • acro-: extremities
  • brady-: slow
  • dia-: through
  • dys-: difficult
  • electro-: electric
  • endo-: within
  • epi-: upon or over
  • hyper-: above normal
  • hypo-: below normal
  • macro-: large
  • micro-: small
  • peri-: around
  • sub-: under, below
  • tachy-: fast

L1.3 Common word roots (Table 1.1)

  • abdomin/o: abdomen
  • aden/o: gland
  • angi/o: vessel
  • arthr/o: joint
  • cardi/o: heart
  • col/o: colon
  • cyan/o: blue
  • cyt/o: cell
  • derm/o: skin
  • erythr/o: red
  • gastr/o: stomach
  • glyc/o: sugar
  • hemat/o, hem/o: blood
  • hepat/o: liver
  • hist/o: tissue
  • hydr/o: water
  • leuk/o: white
  • mamm/o: breast
  • nephr/o: kidney
  • neur/o: nerve
  • oste/o: bone
  • path/o: disease
  • phag/o: to swallow
  • phleb/o, ven/o: vein
  • pne/o or pne/a: to breathe
  • pneumon/o: air or lung
  • rhin/o: nose

L1.3 Common medical suffixes (Table 1.3)

  • -al, -ic: pertaining to or related to
  • -algia: pain
  • -cyte: cell
  • -ectomy: surgical removal or excision
  • -gram: actual record (of tests/results)
  • -graphy: process of recording
  • -ist: one who specializes
  • -itis: inflammation of
  • -megaly: enlargement
  • -ologist or -logist: one who studies
  • -oma: tumor
  • -osis: condition of
  • -otomy: cutting into
  • -ostomy: surgically forming an opening
  • -pathy: disease
  • -penia: decrease or lack of
  • -phobia: fear of
  • -plasty: surgical repair
  • -scope: instrument to view or examine

L1.3 Singular and plural forms (Table 1.2, irregular forms)

  • Singular -> Plural rules (examples):
    • -a -> -ae (pleura -> pleurae)
    • -ax -> -aces (thorax -> thoraces)
    • -en -> -ina (lumen -> lumina)
    • -ex -> -ices (cortex -> cortices)
    • -is -> -es (testis -> testes)
    • -is -> -ides (epididymis -> epididymides)
    • -ix -> -ices (appendix -> appendices)
    • -ma -> -mata (carcinoma -> carcinomata)
    • -on -> -a (ganglion -> ganglia)
    • -um -> -a (septum -> septa)
    • -us -> -era (viscus -> viscera)
    • -us -> -i (villus -> villi)
    • -x -> -ges (phalanx -> phalanges)
    • -y -> -ies (ovary -> ovaries)
    • -yx -> -yces (calyx -> calyces)

L1.3 Directional terms (Table 1.3)

  • Ventral: toward the front/belly. Example: The aorta is ventral to the vertebral column.
  • Dorsal: toward the back/spine. Example: The vertebral column is dorsal to the aorta.
  • Anterior: toward the ventral side (same as ventral in humans).
  • Posterior: toward the dorsal side (back).
  • Superior: above.
  • Inferior: below.
  • Medial: toward the midsagittal plane.
  • Lateral: away from the midsagittal plane.
  • Proximal: closer to the point of attachment/origin.
  • Distal: farther from the point of attachment/origin.
  • Superficial: closer to the body surface.
  • Deep: farther from the body surface.

L1.3 Learning Activity F

  • Prompt: Break down terms into roots, prefixes, and suffixes: electrocardiography, brachiocephalic, hyperkalemia, substernal, pericardial.

L1.3 Learning Activity G

  • Prompt: Write the plural form of: lacuna, nucleus, epithelium, diagnosis.
  • Prompt: Write the singular form of: larynges, ampullae, matrices, ova.

L1.3 Learning Activity H

  • Prompt: Define the location of the following using directional terms:
    • head to the knees
    • heart to the lungs
    • muscles to the skin
    • shoulder to the elbow
    • thumb to the index finger
    • lumbar vertebrae to the scapula

Consolidation and study reminders (L1.62)

  • Review Lecture objectives and Learning Activities in your own time.
  • Access Canvas modules for additional study materials.
  • Attempt all tutorial questions before the next week.
  • Quiz 1: open now; due date: 11:59pm on Sun 3 Aug 2025.
  • Tutorial options:
    • In person (GP216) Tuesdays 12-1pm (after lecture) with Zee; 2-3pm with Zee.
    • Online (Zoom) Wednesdays 10-11am with Bayley; 11am-12pm with Bayley; Zoom link in Canvas.

End of Lecture 1 notes