Tissues and Early Embryology Flashcards

Flashcards covering epithelial, connective, muscle, and neural tissues as well as early embryology based on Chapter 3 of Human Anatomy.

What is an epithelium and what are its primary locations?

An epithelium is a sheet of cells that covers exposed surfaces and lines internal cavities and passageways.

What are the four primary functions of epithelial tissue?

1. Provide physical protection
2. Control permeability
3. Provide sensation
4. Produce secretions

What three structural specializations are found on epithelial cell surfaces?

Microvilli, stereocilia, and ciliated epithelium.

What two layers form the basal lamina anchoring epithelial cells?

The lamina lucida (clear layer) and the lamina densa (dense layer).

How are epithelia categorized based on the number of cell layers?

Simple epithelium consists of a single layer of cells, whereas stratified epithelium consists of several layers of cells.

How are epithelia categorized based on cell shape?

Squamous (thin, flat cells), cuboidal (height equal to width), columnar (height usually 3–4 times width), and transitional (changes shape).

What are the locations and functions of simple squamous epithelium?

Locations: Mesothelia lining ventral body cavities, endothelia lining heart and blood vessels, portions of kidney tubules (thin sections of nephron loops), inner lining of cornea, and alveoli of lungs. Functions: Reduces friction, controls vessel permeability, and performs absorption and secretion.

What are the locations and functions of stratified squamous epithelium?

Locations: Surface of skin; lining of mouth, throat, esophagus, rectum, anus, and vagina. Functions: Provides physical protection against abrasion, pathogens, and chemical attack.

What are the locations and functions of simple cuboidal epithelium?

Locations: Glands, ducts, portions of kidney tubules, and thyroid gland. Functions: Limited protection, secretion, and absorption.

What are the locations and functions of stratified cuboidal epithelium?

Locations: Lining of some ducts (rare). Functions: Protection, secretion, and absorption.

What are the locations and functions of simple columnar epithelium?

Locations: Lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys. Functions: Protection, secretion, and absorption.

What are the locations and function of stratified columnar epithelium?

Locations: Small areas of the pharynx, epiglottis, anus, mammary gland, salivary gland ducts, and urethra. Function: Protection.

What are the locations and functions of pseudostratified ciliated columnar epithelium?

Locations: Lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract. Functions: Protection and secretion.

What are the locations and functions of transitional epithelium?

Locations: Urinary bladder, renal pelvis, and ureters. Functions: Permits expansion and recoil after stretching.

How do serous glands, mucous glands, and mixed exocrine glands differ in their secretions?

Serous glands secrete watery fluids rich in enzymes; mucous glands secrete mucins (glycoproteins that absorb water to form mucus); mixed exocrine glands contain cells capable of both serous and mucous secretions.

How do exocrine glands and endocrine glands differ in their structural formation?

In exocrine gland formation, cells connecting secretory cells to the surface form a duct that carries secretions to the epithelial surface. In endocrine gland formation, connecting cells disappear, and gland cells secrete directly into blood vessels or surrounding tissue fluids.

What three main components make up all connective tissues?

1. Special cells
2. Extracellular protein fibers
3. Ground substance

What constitutes the extracellular matrix of a connective tissue?

The extracellular matrix is composed of the extracellular protein fibers and the ground substance.

What are the primary functions of connective tissues?

Establishing body structural framework, transporting fluid and dissolved materials, protecting organs, supporting/surrounding/connecting other tissues, storing energy, and defending the body from microorganisms.

How are connective tissues classified into major categories?

Connective tissues are divided into Connective Tissue Proper (loose and dense), Fluid Connective Tissues (blood and lymph), and Supporting Connective Tissues (cartilage and bone).

Which cell types are classified as fixed cells in connective tissue proper?

Fibroblasts, fibrocytes, fixed macrophages, adipocytes, mesenchymal cells, and melanocytes.

Which cell types are classified as wandering cells in connective tissue proper?

Free macrophages, mast cells, lymphocytes, and neutrophils and eosinophils.

What are the specific functions of fibroblasts, fibrocytes, and mesenchymal cells?

Fibroblasts produce connective tissue fibers; fibrocytes maintain connective tissue fibers and matrix; mesenchymal cells are stem cells that can differentiate into other cell types.

What are the characteristics of collagen, reticular, and elastic fibers in connective tissue proper?

Collagen fibers are long, cylindrical, strong fibers composed of three coiled subunits; reticular fibers consist of single units of collagen proteins; elastic fibers contain the protein elastin.

What are the locations and functions of areolar tissue?

Locations: Deep to dermis of skin, covered by epithelial lining of digestive, respiratory, and urinary tracts, between muscles, around blood vessels, nerves, and joints. Functions: Cushions organs, provides support while permitting independent movement, and contains phagocytic cells for defense.

What are the locations and functions of adipose tissue?

Locations: Deep to skin (especially sides, buttocks, breasts) and padding around eyes and kidneys. Functions: Provides padding, cushions shocks, insulates against heat loss, and stores energy.

What are the locations and function of reticular tissue?

Locations: Liver, kidney, spleen, lymph nodes, and bone marrow. Function: Provides a supporting framework.

What are the locations and functions of dense regular connective tissue?

Locations: Between skeletal muscles and skeleton (tendons and aponeuroses), between bones or stabilizing internal organs (ligaments), covering skeletal muscles, and deep fasciae. Functions: Provides firm attachment, conducts pull of muscles, reduces friction between muscles, and stabilizes relative positions of bones.

What are the locations and functions of elastic tissue?

Locations: Between vertebrae of spinal column (ligamentum flavum and ligamentum nuchae), ligaments supporting penis, ligaments supporting transitional epithelia, and blood vessel walls. Functions: Stabilizes positions of vertebrae and penis, cushions shocks, and permits expansion and contraction of organs.

What are the locations and functions of dense irregular connective tissue?

Locations: Capsules of visceral organs, periostea and perichondria, nerve and muscle sheaths, and deep dermis. Functions: Provides strength to resist forces applied from many directions and helps prevent overexpansion of organs.

What are the two fluid connective tissues and their fluid matrix sources?

Blood contains a fluid matrix called plasma with formed elements; lymph forms as interstitial fluid is collected into lymphatic vessels to return to blood vessels.

What formed elements are contained in blood?

Red blood cells, white blood cells (monocyte, lymphocytes, eosinophil, neutrophil, basophil), and platelets.

What are the three major types of cartilage?

Hyaline cartilage, elastic cartilage, and fibrous cartilage.

What are the locations and functions of hyaline cartilage?

Locations: Between tips of ribs and sternum, covering bone surfaces at synovial joints, supporting larynx, trachea, and bronchi, and forming part of nasal septum. Functions: Provides stiff but flexible support and reduces friction between bony surfaces.

What are the locations and functions of elastic cartilage?

Locations: Auricle of external ear, epiglottis, auditory canal, and cuneiform cartilages of larynx. Functions: Provides support, tolerates distortion without damage, and returns to original shape.

What are the locations and functions of fibrous cartilage?

Locations: Pads within knee joint, between pubic bones of pelvis, and intervertebral discs. Functions: Resists compression, prevents bone-to-bone contact, and limits relative movement.

What are the four primary types of body membranes?

1. Mucous membranes: wet membranes connected to exterior.
2. Serous membranes: line ventral body cavity.
3. Cutaneous membrane: thick, dry, water-resistant skin.
4. Synovial membranes: areolar tissue with incomplete epithelium lining joint cavities.

What three layers of fascia form the connective tissue framework of the body?

1. Superficial fascia (subcutaneous layer or hypodermis): areolar and adipose tissue between skin and underlying organs.
2. Deep fascia: dense connective tissue forming a strong fibrous internal framework bound to capsules, tendons, and ligaments.
3. Subserous fascia: areolar tissue between serous membranes and deep fascia.

What are the cell characteristics, locations, and functions of skeletal muscle tissue?

Characteristics: Long, cylindrical, striated, multinucleate cells. Locations: Combined with connective tissues and neural tissue in skeletal muscles. Functions: Moves or stabilizes skeleton position, guards entrances/exits, generates heat, and protects internal organs.

What are the cell characteristics, location, and functions of cardiac muscle tissue?

Characteristics: Short, branched, striated cells with usually a single nucleus, interconnected by intercalated discs. Location: Heart. Functions: Circulates blood and maintains hydrostatic blood pressure.

What are the cell characteristics, locations, and functions of smooth muscle tissue?

Characteristics: Short, spindle-shaped, nonstriated cells with a single central nucleus. Locations: Walls of blood vessels and in digestive, respiratory, urinary, and reproductive organs. Functions: Moves food, urine, and secretions; controls respiratory passageway diameter; regulates blood vessel diameter.

What are the two basic cell types of neural tissue and their functions?

Neurons transmit electrical signals through the body, while neuroglia are the supporting cells of neural tissue.

How does aging impact tissue repair and non-regenerative tissues?

Repair and maintenance become less efficient, epithelia thin, and connective tissues become fragile. Cardiac muscle and neural tissue cannot regenerate, causing minor damage to accumulate over time.

What process produces a blastocyst and how long does it take?

Fertilization produces a single-cell zygote containing 46 chromosomes. During cleavage, cell divisions produce a hollow ball of cells called a blastocyst, which takes about a week to complete.

What are the distinct developmental fates of the trophoblast and inner cell mass in a blastocyst?

The outer layer (trophoblast) forms the placenta to nourish the developing embryo, while the inner cell mass forms the actual embryo.

What three primary germ layers organize during the second week of development (Day 14)?

Ectoderm, mesoderm, and endoderm.

What is mesenchyme and what role does it play in development?

Mesenchyme is the first connective tissue to appear in the embryo. It contains star-shaped cells separated by ground substance containing fine protein filaments, gives rise to all other connective tissue forms, and assists in adult connective tissue repair.

What structural developments occur at the embryonic shield and primitive streak around Day 14 and Day 18?

By Day 14, the embryonic shield contains upper ectoderm and underlying endoderm, with superficial cells migrating at the primitive streak to add intermediate mesoderm. By Day 18, the embryo lifts off the shield, and the heart tube and blood vessels begin forming.

What major structures derive from the ectoderm primary germ layer?

Epidermis and skin derivatives (hair follicles, nails, sweat/milk/sebum glands), lining of mouth, salivary glands, nasal passageways, and anus, nervous system (brain and spinal cord), portions of endocrine system (pituitary and suprarenal glands), and portions of skull, pharyngeal arches, and teeth.

What major structures derive from the mesoderm primary germ layer?

Dermis of skin, lining of body cavities (pleural, pericardial, peritoneal), muscular, skeletal, cardiovascular, and lymphoid systems, kidneys and part of urinary tract, gonads and most reproductive tract, supporting connective tissues, and portions of suprarenal glands and reproductive endocrine tissues.

What major structures derive from the endoderm primary germ layer?

Most of digestive system epithelium (except mouth and anus), exocrine glands (except salivary glands), liver, pancreas, most of respiratory system epithelium and mucous glands, portions of urinary and reproductive systems (ducts and gamete stem cells), and thymus, thyroid gland, parathyroid glands, and pancreas.

What major anatomical structures are present in the embryo by Day 28 (after one month)?

Pharyngeal (gill) arches, developing ear, eye, heart bulge, umbilical cord, brain, spinal cord, lung bud, liver bud, midgut, future urinary bladder, tail, and muscle blocks.