anatomy week one and two material

Anatomy

The study of biological structure at various levels of organization.

Gross Anatomy

The branch of anatomy dealing with structures visible to the naked eye, such as bones, organs, muscles, blood vessels, and nerves.

Microscopic Anatomy

The branch of anatomy dealing with micro-structures that require equipment, such as microscopes, to visualize.

Histology

The subdiscipline of anatomy dedicated to the study of tissues.

Embryology

The subdiscipline of anatomy dedicated to the study of embryos.

Physiology

The study of biological function across different levels of organization.

Descent with Modification

Darwin's definition of evolution describing how existing structures and mechanisms undergo small modifications driven by selective pressures.

Anatomical Position

Standard body stance defined as standing upright, feet parallel on the floor, head level with eyes forward, and arms at the sides with palms facing forward.

Axial Body Region

The structural division of the body comprising the head and trunk.

Appendicular Body Region

The structural division of the body comprising the upper and lower limbs.

Anatomical Directional Terms

Relative positional terms used to describe the location of one body structure with respect to another.

Posterior (Dorsal)

Directional term meaning closer to the backside of the body.

Anterior (Ventral)

Directional term meaning closer to the front side of the body.

Medial

Directional term meaning closer to the midline of the body.

Lateral

Directional term meaning farther from the midline of the body.

Proximal

Directional term describing a structure closer to the trunk or point of attachment of a limb.

Distal

Directional term describing a structure farther from the trunk or point of attachment of a limb.

Superior

Directional term meaning toward the head.

Inferior

Directional term meaning away from the head.

Superficial

Directional term meaning located close to the surface of the body.

Deep

Directional term meaning located farther inward from the surface of the body.

Prone

Body position characterized by lying face down.

Supine

Body position characterized by lying face up.

Anatomical Planes

Flat planes or section cuts used to view internal body structures.

Sagittal Plane

Vertical plane running top to bottom that divides the body into left and right portions.

Transverse Plane

Horizontal plane dividing the body into top and bottom portions.

Coronal Plane

Vertical plane dividing the body into front and back portions.

Homeostasis

The ability of an organism to maintain relatively constant internal conditions despite living in a variety of environments.

Negative Feedback Loop

A homeostatic control system where the physiological response negates or reverses the initial stimulus to restore balance.

Positive Feedback Loop

A control mechanism that amplifies the initial stimulus and disrupts homeostasis until an outside factor turns off the response.

Feed Forward Response

An anticipatory physiological response where the body acts in response to a stimulus without directly altering the stimulus itself.

Tissue

A collection of cells serving a common function inside the body, which gives rise to organs.

Epithelial Tissue

Tissue type that creates linings on organ surfaces or lumens, functioning in protection, selective permeability, absorption, secretion, and sensation.

Exchange Epithelia

Epithelial tissue composed of a single layer of flattened cells with pores that permit easy passage of molecules via paracellular movement.

Transport Epithelia

Epithelial tissue composed of columnar or cuboidal cells with tight junctions that regulate transcellular movement via specific membrane transport proteins.

Ciliated Epithelia

Epithelial tissue covered with apical cilia that sweep fluid and particles across the surface.

Kartageners Syndrome

A genetic disorder marked by abnormal or immobile cilia, causing impaired mucus clearance and reversed internal organ placement.

Endocrine Glands

Groups of ductless epithelial cells that secrete products directly into the bloodstream or neighboring interstitial fluid for systemic effects.

Exocrine Glands

Epithelial glands containing ducts through which localized secretions travel onto nearby epithelial surfaces.

Exocrine Gland Architecture

Structural classification of exocrine glands based on duct branching (simple vs. compound) and secretory unit shape (tubular, alveolar, or tubuloalveolar).

Mechanisms of Exocrine Secretion

Classification of exocrine glands based on secretion mechanism: merocrine (exocytosis), apocrine (apical pinching), and holocrine (cell rupture).

Merocrine Secretion

Secretion mechanism where membrane-bound secretory vesicles release products via exocytosis.

Apocrine Secretion

Secretion mechanism where product accumulates at the cell apex and a small portion of cytosol pinches off with the secretion.

Holocrine Secretion

Secretion mechanism where the entire cell ruptures to release its secretory product.

Tight Junctions

Intercellular junctions formed by woven membrane proteins that close the paracellular space between cells to enforce selective transcellular transport.

Adherens Junctions

Intercellular junctions that pass through cell membranes to attach to internal actin filaments and the cytoskeleton.

Desmosomes

Glycoprotein patches on cell membranes containing tetherin proteins that extend across intercellular spaces to provide structural support and flexibility.

Pemphigus Vulgaris

An autoimmune disorder in which autoantibodies attack skin desmosomes, causing cell layer separation and widespread blistering.

Gap Junctions

Intercellular channel junctions that connect the cytoplasm of adjacent cells for electrical and metabolic coupling.

Simple Epithelium

Epithelial tissue composed of a single cell layer.

Stratified Epithelium

Epithelial tissue composed of two or more cell layers.

Pseudostratified Columnar Epithelium

A single layer of columnar cells that appears multi-layered because nuclei are positioned at different heights.

Transitional Epithelium

Stratified epithelium capable of stretching and expanding, found lining organs like the urinary bladder.

Cystic Fibrosis

A genetic disease involving defective CFTR channels, causing cellular accumulation of sodium and chloride, water influx, and abnormally thick mucus blocking airways and lumen walls.

Connective Tissue

The most diverse and abundant tissue type, characterized by low cellular density, abundant extracellular matrix, and structural connection of other tissues.

Extracellular Matrix

The non-cellular space outside cells containing protein fibers (such as collagen and elastin) and ground substance (water and ions).

Connective Tissue Classification

The major classification scheme dividing connective tissues into connective tissue proper, supporting connective tissue, and fluid connective tissue.

Areolar Tissue

Loose connective tissue proper that cushions organs, provides nutrients to epithelia, and contains macrophages to minimize invasion.

Adipose Tissue

Loose connective tissue proper made of fat-storing adipocytes that functions in insulation, organ protection, and lipid storage.

Reticular Tissue

Loose connective tissue proper composed of a mesh of reticular fibers that forms a supportive framework for organs like lymph nodes and the spleen.

Dense Regular Connective Tissue

Connective tissue proper containing tightly packed parallel collagen fibers that yield maximum unidirectional strength and limited flexibility.

Dense Irregular Connective Tissue

Connective tissue proper containing non-parallel collagen fibers providing multidirectional strength and flexibility.

Fluid Connective Tissue

Connective tissue category (blood and lymph) consisting of cells and proteins suspended in a liquid matrix.

Compact Bone

Dense bone tissue located closest to the outer surface designed to absorb mechanical force and prevent fractures.

Spongy Bone

Porous bone tissue located deep within bone organs, composed of a lattice of trabeculae containing red bone marrow.

Long Bone Anatomy

Anatomical organization of long bones featuring a diaphysis shaft, epiphysis ends, periosteum, and medullary cavity.

Diaphysis

The tubular shaft of a long bone composed of compact bone.

Epiphysis

The expanded end of a long bone composed primarily of spongy bone.

Osteon

The basic structural unit of compact bone consisting of concentric lamellae surrounding a central canal.

Periosteum

Outer fibrous connective tissue layer surrounding bone that carries blood vessels and osteoblasts.

Osteoblasts

Bone-building cells that synthesize and secrete new bone matrix.

Osteocytes

Mature bone cells located inside lacunae that maintain healthy bone tissue.

Osteoclasts

Bone-recycling cells that break down bone matrix to release calcium into the bloodstream.

Chondroblasts

Immature cartilage cells that actively secrete matrix.

Chondrocytes

Mature cartilage cells that reside in lacunae and maintain the cartilage matrix.

Hyaline Cartilage

Cartilage with a flexible gel-like matrix that cushions organs and supports tissues.

Fibrocartilage

Cartilage with parallel collagen fibers embedded in its matrix for superior shock absorption.

Elastic Cartilage

Cartilage rich in elastin fibers providing increased flexibility.

Interstitial Growth

Cartilage growth from within, where chondrocytes in lacunae undergo mitosis and secrete matrix to separate.

Appositional Growth

Cartilage growth along the periphery, where stem cells in the perichondrium divide into chondroblasts to add matrix externally.

Epiphyseal Plate

A hyaline cartilage zone in long bones where chondrocytes proliferate and ossify, enabling longitudinal bone growth.

Endochondral Ossification

The developmental process where a hyaline cartilage model is replaced by bone tissue.

Metaplasia

The reversible replacement of one differentiated tissue type by another tissue type in response to chronic irritation.

Hypertrophy

Tissue growth characterized by an increase in individual cell size in the absence of cell division.

Hyperplasia

Tissue growth characterized by an increased rate of normal cell division leading to higher cell numbers.

Neoplasia

Uncontrolled, abnormal cell growth forming tissue masses or tumors.

Apoptosis

Programmed, non-inflammatory cell death where cells condense and are systematically replaced.

Necrosis

Uncoordinated, premature cell death resulting from injury, provoking an inflammatory immune response.

Stem Cell Potency

The measure of the spectrum of differentiated cell types that a stem cell can give rise to.

Totipotent Stem Cell

An early embryonic stem cell capable of giving rise to an entire organism, including both embryonic body cells and the placenta.

Pluripotent Stem Cell

A stem cell capable of developing into almost all cell types of the body, but unable to form placenta or an entire organism.

Multipotent Stem Cell

A stem cell capable of differentiating into a limited suite of cell types within a specific lineage.

Unipotent Stem Cell

A stem cell capable of producing only a single specific cell type.

Keratinocytes

Epidermal cells that produce keratin, a hard protective protein.

Melanocytes

Epidermal cells that produce the protective pigment melanin.

Langerhans Cells

Dendritic immune cells residing in the epidermis that assist in immune defense.

loose connective tissue

flexible mesh

dense connective tissue

packed tight, strong, not flexible

central canal

runs through osteons and contains blood vessels

lamellae

layer of hard tissue that radiates out of central canal composed of calcium salts and hard bony matrix