Anatomy and Physiology Overview
Anatomy and Physiology
- Definition: Anatomy refers to the structure and placement of muscles and bones, while physiology explains their functions.
- Importance of Proper Function: Correct anatomical positions are crucial for optimal bodily function; deviations can result in complications or even death.
Planes of the Body
- Sagittal Plane: Divides the body into left and right halves along the spine.
- Medial Plane: A central line that creates equal left and right halves across the body.
- Transverse Plane: Divides the body into cranial (head) and caudal (tail) sections.
- Dorsal Plane: Separates the dorsal (back) and ventral (belly) cavities.
Anatomical Terminology
- Cranial vs. Rostral: Cranial is used relative to the head, while rostral refers to the nose; cranial would be confusing if studied from above.
- Ventral vs. Dorsal: Ventral refers to the belly side (e.g., left hand on abdomen) while dorsal refers to the back side (e.g., right hand on the back).
- Proximal vs. Distal: Proximal is closer to the base of the body, distal is farther away.
- Medial vs. Lateral: Medial refers to the inner side of the limb, lateral refers to the outer side.
- Deep vs. Superficial: Deep refers to structures further away from the surface, while superficial is closer to the surface.
Body Tissues
- Cell: Basic structural unit capable of life.
- Tissue: Group of similar cells working together for a specific function.
- Organ: Composed of different tissues working together.
- Organ System: Groups of organs functioning together.
Major Tissue Types
- Epithelial Tissue:
- Functions: Protection, secretion, absorption, filtration, sensory input, and lining of cavities.
- Characteristics: Polar cells with an apical (top) and basal (base) surface; avascular (lack blood vessels).
- Connective Tissue:
- Functions: Provides support, binds other tissues together, transports substances, and stores energy.
- Types: Loose, dense, specialized (blood, cartilage, etc.).
- Muscle Tissue:
- Functions: Movement and contraction composed of actin and myosin.
- Types: Smooth (involuntary), skeletal (voluntary), and cardiac (heart).
- Nervous Tissue:
- Composed of neurons and supporting neuroglial cells.
- Functions: Receives and transmits electrical signals.
Epithelial Characteristics
- Avascular: Rely on connective tissue for nutrients and oxygen.
- Junctions:
- Tight Junctions: Prevent leaks; important in organs where containment is necessary.
- Desmosomes: Provide mechanical strength; common in high-stress areas like skin.
- Gap Junctions: Allow communication and ion exchange; found in heart and smooth muscles.
Types of Epithelial Tissue
- Simple Epithelium: One layer of cells (e.g., simple squamous in lungs, cuboidal in glands).
- Stratified Epithelium: Multiple layers (e.g., in skin, mouth).
- Pseudostratified: Appears layered but each cells touches the base.
- Transitional Epithelium: Accommodates stretching (e.g., urinary bladder).
Glands
- Definition: Cells or groups of cells that produce and secrete substances.
- Types of Glands:
- Endocrine Glands: No ducts; secrete hormones directly into the bloodstream (e.g., pituitary).
- Exocrine Glands: Have ducts; secrete locally (e.g., sweat glands).
Connective Tissue
- Components: Made up of cellular components (fibroblasts, leukocytes), fibers (collagen, elastic), and ground substance.
- Functions: Structural support, transportation (blood), and storage (adipose).
Muscle Tissue
- Skeletal Muscle: Striated and voluntary.
- Smooth Muscle: Non-striated and involuntary.
- Cardiac Muscle: Striated, involuntary, and branched.
Inflammation and Healing Process
- Inflammation Stages:
- Vasoconstriction followed by vasodilation (swelling, redness).
- Fluid enters from plasma, causing swelling and pain.
- Clot formation helps isolate injury.
- Phagocytes clear debris.
- Formation of granulation tissue beneath damaged areas.
- Healing may occur through primary or secondary intention depending on the wound type.
