Anatomy & Physiology Unit 1-3

Unit 1: Introduction to Anatomy & Physiology

1. Differentiating Anatomy & Physiology

Anatomy: The study of body structure and functions.
Physiology: The study of dynamic processes in a living body.

2. Key Terms & Definitions

Pathology: The study of disease.
Pathophysiology: The study of the function of disease; specifically when homeostatic control fails.
Histology: The study of the microscopic structure of tissues and organs.
Cytology (cell biology): The study of cellular structure and function.
Embryology: The study of prenatal development.

3. Levels of Organization in the Human Body

Chemical (molecular) level: Atoms --> molecules --> macromolecules --> organelles --> cells.
Cellular level: The smallest unit of an organism that carries out all basic functions of life. Each cell is enclosed in a plasma membrane.
Tissue level: A group of similar cells and cell products. Four types: epithelial, connective, muscular, nervous.
Organ level: Composed of $2+$ tissue types that carry out a particular function (e.g., heart, skin, muscles, bones).
Organ system level: A group of organs that carry out a basic function (e.g., circulation, respiration, digestion). There are $11$ organ systems.
Organism level: Formed with a group of organ systems.

4. The 11 Major Body Systems and Their Functions

Integumentary system: Protection, water retention, thermoregulation, Vitamin D synthesis, cutaneous sensation, nonverbal communication. Includes skin, hair, nails, cutaneous glands.
Skeletal system: Support, movement, protective enclosure of viscera, forms blood, mineral storage, electrolyte and acid-base balance. Includes bones, cartilages, ligaments.
Muscular system: Movement, stability, communication, control body openings, heat production. Primarily skeletal muscles.
Nervous system: Rapid internal communication, coordination, motor control & sensation. Includes brain, spinal cord, nerves, ganglia.
Digestive system: Nutrient breakdown, absorption. Liver functions include metabolism of carbs, fat, vit, minerals, protein; synthesis of plasma proteins; disposal of drugs, toxins & hormones; cleansing blood. Includes teeth, tongue, salivary glands, esophagus, stomach, intestines, liver, gallbladder, pancreas.
Endocrine system: Hormone production; internal chemical communication & coordination. Includes testes, ovaries, pituitary gland, pineal gland, thyroid gland, parathyroid glands, thymus, adrenal glands, pancreas.
Respiratory system: Absorb oxygen, discharge $CO_2$ , acid-base balance, speech. Includes nose, pharynx, larynx, trachea, bronchi, lungs.
Cardiovascular system (circulatory): Distribute nutrients, oxygen, wastes, hormones, electrolytes, heat, immune cells, and antibodies; fluid, electrolyte & acid-base balance. Includes heart, blood vessels.
Urinary system: Eliminate waste, regulate blood volume & pressure; stimulate RBC formation, control fluid, electrolyte and acid-base balance; detoxification. Includes kidneys, ureters, urinary bladder, urethra.
Lymphatic system (Immune System): Physical barriers, immune cells, antimicrobial proteins that destroy pathogens before they cause disease. Recover excess tissue fluid, detect pathogens, produce immune cells, defend against diseases. Includes lymph nodes, lymphatic vessels, thymus, spleen, tonsils.
Reproductive system:
- Male: Produce and deliver sperm; secrete sex hormones. Includes testes, epididymides, spermatic ducts, seminal vesicles, prostate gland, bulbourethral glands, penis.
- Female: Produce egg, site of fertilization & fetal development & nourishment; birth, lactation; secrete sex hormones. Includes ovaries, uterine tubes, uterus, vagina, mammary glands.

5. The Anatomical Position

Anatomical position: Standing upright, head and face forward, feet shoulder-width apart, arms at sides, palms facing forward and thumbs out.

6. Directional Planes

Sagittal Plane: Divides the body into left and right portions.
Frontal (coronal) Plane: Divides the body into anterior (front) and posterior (back) portions.
Transverse Plane: Divides the body horizontally into superior (upper) and inferior (lower) portions.

7. Directional Terms

Superior: Toward the head or upper part of a structure or body; above. Ex: The forehead is superior to the nose.
Inferior: Toward the feet or toward the lower part of a structure or body; below. Ex: The navel is inferior to the breastbone.
Anterior or Ventral: Toward or at the front of the body; in front of. Ex: The breastbone is anterior to the spine. (Synonymous for humans; 'ventral' for belly of animal).
Posterior or Dorsal: Toward or at the backside of the body; behind. Ex: The heart is posterior to the breastbone. (Synonymous for humans; 'dorsal' for back of animal. Dorsal surface of legged animals is their superior surface).
Medial: Toward or at the midline of the body; on the inner side of. Ex: The heart is medial to the arm.
Lateral: Away from the midline of the body; on the outer side. Ex: The arms are lateral to the chest.
Proximal: Close to the origin of the body part or the point of attachment of a limb (closer to torso). Ex: The elbow is proximal to the wrist (the elbow is closer to the shoulder or to the body trunk/closer to torso attachment point of the arm than the wrist).
Distal: Farther from the origin of a body part or the point of attachment of a limb (further from torso). Ex: The knee is distal to the thigh (the knee is further from torso than the thigh).
Superficial: Toward or at the body surface. Ex: The skin is superficial to the skeleton.
Deep: Away from the body surface; more internal. Ex: The lungs are deep to the ribcage.
Intermediate: Between a more medial and a more lateral structure. Ex: The armpit is intermediate between the breastbone and shoulder.

8. Major Body Cavities

Dorsal cavity:
- Cranial cavity: Organs contained within: Brain.
- Vertebral cavity: Organs contained within: Spinal cord.
Ventral cavity:
- Thoracic cavity: Organs contained within: Lungs, heart, esophagus, trachea, thymus.
- Abdominopelvic cavity: Organs contained within: Stomach, intestines, liver, spleen, pancreas, kidneys, urinary bladder, reproductive organs.

9. The Diaphragm

Diaphragm: A muscular sheet that separates the thoracic and abdominopelvic cavities. Its contraction and relaxation are key for respiration (breathing).

10. Abdominopelvic Regions

R. & L. Hypochondriac: Upper lateral regions below the ribs.
Epigastric: Upper central region, above umbilical.
R. & L. Lumbar: Middle lateral regions, beside umbilical.
Umbilical: Central region, around the navel.
R. & L. Inguinal (iliac): Lower lateral regions, near the groin.
Hypogastric: Lower central region, below umbilical (pubic area).

11. Abdominopelvic Quadrants

Right Upper Quadrant (RUQ)
Left Upper Quadrant (LUQ)
Right Lower Quadrant (RLQ)
Left Lower Quadrant (LLQ)

12. Body Regions

Abdominal, Acromial, Antebrachial, Antecubital, Axillary, Brachial, Buccal, Carpal, Calcaneal, Cephalic, Cervical, Coxal, Cranial, Crural, Cubital, Cutaneous, Deltoid, Digital, Facial, Femoral, Frontal, Gluteal, Inguinal, Lumbar, Mammary, Manual, Mental, Nasal, Occipital, Olecranal, Oral, Orbital, Palmar, Patellar, Pedal, Pelvic, Perineal, Plantar, Popliteal, Pubic, Sacral, Scapular, Sternal, Tarsal, Temporal, Thoracic, Umbilical, Vertebral, Zygomatic.

13. Homeostasis

Homeostasis: A self-regulating process to maintain the stability of the internal environment within a narrow range despite any external changes.

14. Feedback Loop Components

Feedback loop: A cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored, and reevaluated.
1. Receptor: Senses changes.
2. Integrating Center: Processes information, relates it to other available information, and makes a decision on the appropriate response.
3. Effector: A cell or organ that carries out the final corrective action.
4. Response: Return to homeostasis; feedback loop is complete.

15. Types of Feedback Loops

Negative feedback loop (mechanism): The body senses a change and activates mechanisms to reverse it. It's the most common type. Ex: Blood pressure regulation, blood glucose control.
Positive feedback loop (mechanism): A self-amplifying cycle that enhances change in the same direction. Ex: Childbirth contractions.

Unit 2: Body Tissues

1. Four Primary Tissues of the Body

Epithelial tissue
Connective tissue
Nervous tissue
Muscular tissue

2. Defining Characteristics of Primary Tissues

Types and functions of their cells.
The characteristics of the matrix (extracellular material) that surrounds the cells.
The relative amount of space occupied by cells vs. matrix.

3. Epithelial Tissue Description

Shape and arrangement of cells: Flat sheet of closely spaced cells, one or more cells thick, like bricks in a wall.
Basement membrane: A layer between epithelium and connective tissue, composed mainly of protein. Anchors epithelium to underlying connective tissue.
Apical versus basal: Apical = surface facing body surface or internal cavity (lumen); Basal = surface of dell attached to basement membrane; Lateral = sides of the cell.
Intercellular matrix: Primarily limited to the basement membrane.
Blood and nerve supply: Contains no blood vessels (avascular); almost always rests on a layer of loose connective tissue and depends on its blood vessels for nourishment and waste removal. Has nerve supply.
Ability to regenerate: Highly regenerative.
Overall functions: Protection, secretion, excretion, absorption, filtration, sensation.

4. Epithelial Cell Shapes

Squamous: Thin, flat, scaly, $6-$ sided (fried egg shape).
Cuboidal: Square, cubed, $6-$ sided round.
Columnar: Tall, narrow, rectangle or $6-$ sided.

5. Simple vs. Stratified Epithelium

Simple epithelium: One layer of cells (every cell touches the basement membrane).
Stratified epithelium: Ranges from $2$ cell layers to $20$ or more.

6. Types of Epithelial Tissue: Structure, Function, Location

Simple squamous:
- Structure: Single layer of thin, flat cells.
- Function: Rapid diffusion or transport of substances through membranes; secretes lubricating serous fluid.
- Location: Air sacs (alveoli) of lungs, glomerular capsules of kidneys, kidney tubules, lining of heart & blood vessels; serous membranes of stomach, intestines, surface layer of pleura, peritoneum, and mesenteries.
Simple cuboidal:
- Structure: Single layer of squarish cells.
- Function: Absorption and secretion; production of protective mucous; movement of respiratory mucus.
- Location: Liver, thyroid, mammary, salivary, and other glands; many gland ducts; most kidney tubules; bronchioles.
Simple columnar:
- Structure: Single layer of tall, narrow cells.
- Function: Absorption and secretion; movement of egg and embryo in uterine tube; secretion of mucus.
- Location: Inner lining of stomach, intestines, gallbladder, uterus, and uterine tubes; some kidney tubules.
Pseudostratified columnar:
- Structure: Not all cells reach the free surface; shorter cells are covered by taller ones, but all of them reach the basement membrane (simple epithelium appearance, but looks stratified).
- Function: Secretes and propels respiratory mucus; absorbs excess fluid from parts of male reproductive tract.
- Location: Respiratory tract from nasal cavity to bronchi; portions of male reproductive tract.
Stratified squamous:
- Structure: Multiple layers of thin cells. Keratinized: Dead cells, surface appearance gets increasingly flat. Nonkeratinized: Not dead cells (living).
- Function: Keratinized: Resists abrasion, retards water loss; resists penetration by pathogenic organisms. Nonkeratinized: Resists abrasion & penetration by pathogenic organisms while providing a very slippery surface.
- Location: Keratinized: Epidermis; especially palms & soles. Nonkeratinized: Tongue, oral mucosa, esophagus, anal canal, vagina.
Stratified cuboidal:
- Structure: Two or more layers of cells; surface cells are squarish or rounded.
- Function: Contributes to sweat secretion; secretes ovarian hormones; produces sperm.
- Location: Sweat gland ducts; egg-producing vesicles (follicles) of ovaries; sperm-producing ducts of testes.
Stratified columnar:
- Structure: Multiple layers of tall, narrow cells on the surface, and smaller (cuboidal or columnar) cells in the deeper layers.
- Function: Protection & secretion of mucus.
- Location: Male urethra, anus, large ducts of exocrine glands.
Transitional:
- Structure: Resembles stratified squamous but surface cells are rounded, not flattened; some cells have two nuclei. The number of layers can change depending on stretch.
- Function: Stretches to allow filling of urinary tract; protects deeper cells and tissues from damage by acidic & hypertonic urine.
- Location: Limited to urinary tract (part of kidney, ureter, bladder, part of urethra).

7. Connective Tissue Description

Structural characteristics:
- Cells vs. matrix: Matrix is greater than the volume occupied by cells. Cells are not in direct contact with each other; they are separated by the matrix.
- Fibers:
  - Collagen: Tough, flexible, resists stretching, most abundant protein. Provides support.
  - Reticular: Thin, forms a spongelike framework.
  - Elastic: Thinner than collagen, made of stretchy protein (elastin), allows stretch & recoil.
General functions: Binding of organs, support, physical protection, immune protection, transport, movement, storage (fat for energy, bone for calcium & phosphorus), heat production.

8. Types of Connective Tissue: Structure, Function, Location

Fibrous – Loose: Areolar:
- Structure: Lots of space; loose, random arrangement of elastic and collagen fibers; scattered cells of various types.
- Function: Loosely binds epithelia to deeper tissues; allows passage of nerves & blood vessels through other tissues; arena for immune defense; blood vessels provide nutrients and waste removal for overlying epithelia.
- Location: Under all epithelia, surrounding blood vessels, esophagus, trachea; fascia between muscle; arena for immune defense.
Fibrous – Loose: Reticular:
- Structure: Loose network of reticular fibers, reticular cells and fibroblasts; numerous lymphocytes & other blood infiltrated cells with supportive stroma (framework).
- Function: Forms supportive stroma (framework) for lymphatic organs.
- Location: Lymph nodes, spleen, thymus, bone marrow.
Fibrous – Dense: Dense regular:
- Structure: Densely packed, parallel, often wavy collagen fibers.
- Function: Stabilize joints, resist stress.
- Location: Tendons, ligaments, vocal cords, arteries.
Fibrous – Dense: Dense irregular:
- Structure: Densely packed collagen fibers in random directions.
- Function: Durable; variable orientation of fibers withstands stresses applied in unpredictable directions.
- Location: Deeper portion of dermis of skin; capsules around viscera such as liver, kidney, spleen; fibrous sheaths around cartilages, bones and nerves.
Adipose:
- Structure: Dominated by adipocytes (large, empty-looking cells); nucleus pressed against plasma membrane; blood vessels often present.
- Function: Energy storage, thermal insulation, protective cushion, fill space, body shape, heat protection by brown fat.
- Location: Fat, breast, heart surface, mesenteries; surrounding organs such as kidneys & eyes.
Bone:
- Structure: Hard, calcified connective tissue arranged in concentric lamellae around central canals.
- Function: Physical body support; leverage for muscle action; protective enclosure of viscera; reservoir of calcium and phosphorus.
- Location: Skeleton.
Cartilage:
- Structure: Supportive connective tissue more flexible than bone but still firm; helps reduce friction (Hyaline, elastic, fibrocartilage).
- Function: Provides more support and flexibility than bone; resists compression and absorbs shock.
- Location: Joints, trachea, bronchi, ear, nose.
Blood:
- Structure: Fluid matrix with WBCs, RBCs and platelets; WBCs also occupy loose connective tissues. Platelets secrete growth factors that promote tissue maintenance and repair.
- Function: Transport gas, nutrients, waste, chemical signals, heat; provides defensive leukocytes; clotting agents.
- Location: Heart, blood vessels.

9. Muscle Tissue Characteristics

Structural characteristics:
- Skeletal: Striated (visible vertical stripes). Long, threadlike, unbranched muscle fibers; relatively parallel; each cell with multiple nuclei near the plasma membrane. Mostly in bone but also tongue, anus, urethra.
- Cardiac: Striated. Short, branched cells; less parallel; thicker dark bands; usually one nucleus per cell, centrally located. Found in the heart only.
- Smooth: Non-striated. Short, tapered, overlapping cells; one nucleus per cell, centrally located. Found in walls of viscera, iris, hair follicle association, involuntary sphincters of urethra and anus.
Functional characteristics:
- Skeletal: Body movements, facial expression, posture, breathing, speech, swallowing, control urination & defecation, childbirth (voluntary control).
- Cardiac: Pumping blood under involuntary control.
- Smooth: Swallowing; stomach & intestine contractions; retention & expulsion of feces & urine; labor contractions; control blood pressure, respiratory airflow, pupillary diameter, erection of hairs (under involuntary control).

10. Nervous Tissue Characteristics

Structural characteristics: A few large neurons with rounded or stellate cell bodies and fibrous processes (axons & dendrites) extending from somas; neurons surrounded by many smaller glial cells.
Functional characteristics: Internal communication.
- Location: Brain, spinal cord, nerves, ganglia.

Unit 3: The Integumentary System

1. Membrane Definition

Membrane: A thin layer that forms the outer boundary of a living cell or an internal cell compartment.

2. Functions of Body Membranes

Covers and protects body surfaces.
Lines body cavities.
Anchors organs and structures.
Secretes lubricating fluids to reduce friction.
Acts as a barrier against pathogens and harmful substances.

3. Types of Membranes

Mucous membranes (Mucosal): Absorptive, secretive & protective function; trap & eliminate bacteria. Lines body cavities open to the outside (e.g., respiratory, digestive, urinary, reproductive tracts).
Serous membranes (Serosal): Lubrication function. Lines body cavities that are closed off to the external environment.

4. Types of Epithelial Membranes

Cutaneous (Skin)
Mucous membrane
Serous membrane

5. Serous Membrane Description

Structural characteristics: Simple squamous epithelium resting on thin areolar connective tissue.
Basement membrane: Rests on a thin basement membrane, anchors epithelium to connective tissue.
Secretion: Watery serous fluid (serum).
Location in the body: Lines the thoracic & abdominal cavities and covers the external surfaces of organs (has exit routes for fluid). Forms two layers:
- Parietal layer: Lines the cavity.
- Visceral layer: Covers/surrounds the structure in the cavity.

6. Serous Membrane Related Terms

Peritoneum: Serosa found in the abdominopelvic area ( $2-$ layered).
- Parietal peritoneum: Lines the abdominal cavity.
- Visceral peritoneum: Surrounds the external surface of abdominal organs (stomach, intestines, etc.).
- Mesentery: $2$ layers of visceral peritoneum, supporting organs and containing blood vessels and nerves.
Pleura: Serosa found in the thoracic area (lungs).
- Parietal pleura: Lines the thoracic cavity.
- Visceral pleura: Surrounds the surface of the thoracic organs (lungs).
- Mediastinal Septum: $2$ sheets of parietal pleura with no space, forming a partition between the pleural cavities in the mediastinum (the space between the lungs).
Pericardial/Pericardium: Serosa found surrounding the heart. Lines the heart cavity.

7. Mucous Membrane Description

Structural characteristics: Epithelium (usually nonkeratinized stratified squamous, simple columnar, or pseudostratified columnar) resting on connective tissue (lamina propria).
Secretions: Mucus (thick) secreted by goblet cells, multicellular mucous glands, or both.
Location in the body: Lines body cavities opened to the outside (respiratory, digestive, urinary & reproductive tracts) (no exit).

8. Layers of the Cutaneous Membrane (Skin)

Epidermis: Superficial layer. Keratinized (dead) stratified squamous epithelium ( $30$ or $40$ cells thick). Composed of keratinocytes, dendritic cells, melanocytes, tactile cells, stem cells.
Dermis: Deeper connective tissue layer. Consists of collagen, elastic & reticular fibers. Supplied with blood vessels, sweat glands, sebaceous glands, nerve endings.

9. Functions of the Skin

Protection: Resists trauma and infection; a protective acidic film kills bacteria when in contact; water retention.
Temperature regulation: Stabilizes body temperature by regulating heat exchange (e.g., sweating).
Sense organ activity: Largest sense organ, various nerve endings react to temperature, pain, injury, vibration, texture, pressure.
Vitamin D Synthesis: Essential for bone development & maintenance.
Nonverbal Communication: Facial muscles on dermis allow for expressions.

10. The Hypodermis (Subcutaneous Tissue)

Hypodermis: Located between the dermis and muscles. Composed of loose connective tissue (adipose). It is not considered part of the skin itself but anchors the skin to underlying structures and provides insulation and energy storage.

11. Epidermis Description

Stratum basale (germinativum): Deepest layer, single layer of stem cells, keratinocytes, melanocytes, tactile cells. Wavy boundary between epidermis and dermis.
Stratum corneum: Outermost layer; up to $40$ layers of keratinized, keratin-packed keratinocytes. Keratinocytes repel water and provide protection. Cells are cuboidal to flat as they go up the surface.
Keratinocytes: Majority of epidermal cells; packed with tough protein keratin; provide water protection.
Melanocytes: Deepest layer of epidermis; produce melanin pigment; protects from UV radiation.
**Other epidermal strata (mentioned in margin):
- Stratum Spinosum: Many layers of keratinocytes with dendritic cells; keratin accumulation flattens cells.
- Stratum Granulosum: $3-5$ layers of flat keratinocytes; protein barrier cuts cells off from nutrients from below; cells die/are dead here.
- Stratum Lucidum: Found in thick skin (soles & palms); thin, clear layer of dead cells with no nuclei or visible internal structure.

12. Dermis Description

Structural characteristics: Thick, strong connective tissue that contains fibers & collagen for flexibility & protection. Hard nails are rooted here; stores blood vessels, nerves & glands.
Dermal papillae: Upward waves, fingerlike extensions of dermis; form friction ridges (fingerprints); resists slippage of epidermis across dermis; provides resistance to stress; abundance of capillaries, source of nourishment for epidermis.

13. Cyanosis

Cyanosis: Blueness of skin from oxygen deficiency in blood, from causes like drowning, lung diseases, and reduced dermal blood flow in cold water.

14. Hair Components: Location, Structure, Function

Follicle:
- Location: Everywhere on body except lips, nipples, parts of genitals, palms & soles, lateral surfaces of fingers and toes.
- Structure: Diagonal tube of epithelium & connective tissue.
- Function: Encases the hair root and produces the hair.
Root:
- Location: Hair below the skin surface in the dermis.
- Structure: The part of the hair embedded in the follicle.
- Function: Anchors and extends the hair.
Shaft:
- Location: Hair visible above skin surface.
- Structure: The part of the hair extending above the skin surface.
- Function: Protection; primary visible part of hair.
Bulb:
- Location: In the dermis, at the base of the follicle.
- Structure: The swelling at the end of the root. Contains the only living cells of the hair.
- Function: Contains the matrix, where hair growth occurs; receives nourishment from the dermal papilla.
Piloerector muscle:
- Location: In the dermis, attached to the hair follicle.
- Structure: Smooth muscle fibers.
- Function: Contracts in response to cold, fear & touch, making the hair stand (causes