Ch. 3 - Tissues and Early Embryology Flashcards
Tissue
Collections of specialized cells and cell products that perform a relatively limited number of functions
Primary Tissue Types
- Epithelial
- Connective
- Muscle
- Neural
Epithelium
A sheet of cells that covers an exposed surface or lines an internal cavity or passageway
Basal lamina
Complex structure produced by the epithelium and cells of the underlying connective tissue where typical epithelium is bound to
Avascular
Do not contain blood. Nutrients are obtained by diffusion or absorption across the apical or basal surfaces
Neuroepithelium
Specialized sensory epithelium found in special sense organs that provide the sensations of smell, taste, sight, equilibrium, and hearing
Gland Cells
Epithelial cells that produce secretions
Glandular epithelium
Most or all epithelial cells produce secretions
Characteristics of Epithelial Tissue
- Cellularity, polarity
- Attachment
- Avascularity
- Arranged into sheets or layers
- Regeneration
Functions of Epithelial Tissue
- Provide physical protection
- Control permeability
- Provide sensation
- Produce specialized secretions
Apical Surface
Where the cell is exposed to an internal or external environment
Basolateral Surface
Where the epithelium contacts the basal lamina and neighboring epithelial cells
Simple Epithelium
Only a single layer of cells cover basal lamina
Stratified Epithelium
Two or more layers of cells above the basal lamina
Squamous Epithelium
The cells are thin, flat, and somewhat irregular in shape. In a sectional view the nucleus occupies the thickest portion of each cell, and has a flattened shape similar to that of the cell as a whole; from the surface, the cells look like fried eggs laid side by side.
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; alveoli of lungs
Functions: reduces friction; controls vessel permeability; performs absorption and secretion
Components: cytoplasm and nucleus
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
Components: connective tissue, basal lamina on top w/ stem cells, and squamous superficial cells on top
Keratinized
A protein that occurs where mechanical stress and dehydration are potential poblems. Located on apical layers of epithelial cells to make superficial layers both tough and water resistant
Non-Keratinized
Provides resistance to abrasion to epithelial, but epithelial will dry out and deteriorate unless kept moist
Cuboidal Epithelium
Resemble little hexagonal boxes; they appear square in typical sectional views. Each nucleus s near the center of the cell, which the distance between adjacent nuclei roughly equal to the height of the epithelium.
Simple Cuboidal Epithelium
Locations: glands; ducts; portions of kidney tubules; thyroid gland
Functions: limited protection, secretion, absorption
Components: basal lamina w/ cuboidal cells on top and nucleus in center
Stratified Cuboidal Epithelium
Locations: lining of some ducts (rare)
Functions: protection, secretion, absorption
Components: lumen of duct, stratified cuboidal cells w/ nucleus in center and connected to basal lamina
Columnar Epithelial
Like cuboidal cells, they’re also hexagonal in cross section. In contrast to cuboidal cells though, their height is much greater than their width. The nuclei are crowded into a narrow band close to the basal lamina, and the height of the epithelium is several times th distance between two nuclei.
Simple Columnar Epithelium
Locations: lining of stomach, intestine, gallbladder, uterine tubes, and collecting ducts of kidneys
Functions: protection, secretion, absorption
Components: microvilli, cytoplasm, nucleus close to basal lamina, loose connective tissue
Stratified Columnar Epithelium
Locations: small areas of the pharynx, epiglottis, anus, mammary gland, salivary gland ducts, and urethra
Function: protection
Components: superficial columnar cells towards lumen
Pseudostratified Ciliated Columnar Epithelium
Locations: lining of nasal cavity, trachea, and bronchi; portions of male reproductive tract
Functions: protection, secretion
Components: cilia on top, cytoplasm, nuclei, basal lamina
Transitional Epithelium
Locations: urinary bladder; renal pelvis; ureters
Functions: permits expansion and recoil after stretching
Components: epithelium (relaxed), basal lamina, connective tissue and smooth muscle layers
Exocrine Glands
A type of secretion
Secretions discharged onto surface of the skin or onto an epithelial surface lining one of the internal passageways that communicates with the surface lining of the internal passageways that communicates with the exterior through an epithelial duct that is connected to the surface of the skin or epithelial surface.
Endocrine Glands
A type of secretion
Secretions are released by exocytosis from the gland cells into the fluid surrounding the cell.
Serous Glands
Exocrine gland
Secrete a watery solution that usually contains enzymes, such as the salivary amylase in saliva.
Mucous Glands
Exocrine gland
Secrete glycoproteins called mucins that absorb water to form a slippery mucus, such as the mucus in saliva
Mixed Excocrine Glands
Exocrine gland
Contains more than one type of gland cell and may produce two different exocrine secretions, one serous, and the other mucous.
Hormones
Secreted by endocrine. They diffise into the blood for distribution to other regions of the body, where they regulate or coordinate the activities of various tissues, organs, and organ systems
Unicellular Glands
A type of gland structure
The individual secretory cells in epithelia that contains scattered glands. These glands secrete mucins.
Multicellular Glands
A type of gland structure
Include glandular epithelia and aggregations of gland cells that produce exocrine or endocrine secretions
Merocrine Secretion
A mode of secretion
The secretory product is released through exocytosis
Apocrine Secretion
A mode of secretion
Involves the loss of cytoplasm as well as the secretory product. The apical portion of the cytoplasm becomes packed with secretory vescicles before it is shed.
Holocrine Secretion
A mode of secretion
Destroys the gland cell. The entire cell becomes packed with secretory products and then bursts apart.
Connective Tissues
Tissues found throughout the body but are never exposed to the environment outside the body.
Ground Substance
A fluid substance
Non-fibrous portion of the extracellular matrix.
Functions of Connective Tissue
- Framework for body
- Transporting fluids and dissolved materials
- Protection for delicate organs
- Supporting, surrounding, and interconnecting other tissue types
- Storing energy reserves
- Defending the body from invasion by microorganisms
Fixed Cells
Connective tissue proper cell type
Stationary and are involved primarily with local maintenance, repair, and energy storage
Wandering Cells
Connective tissue proper cell type
Concerned primarily with the defense and repair of damaged tissues.
Mesenchymal Cells
Type of fixed cell
Stems cells
Fibroblasts
Type of fixed cell
Produce tissue fibers
Fixed Macrophages
Type of fixed cell
Engulf damaged cells or pathogens that enter the tissue
Adipocytes
Type of fixed cell
Fat cells
Melanocytes
Type of fixed cell
Synthesize and store a brown pigment called melanin which gives the tissue a dark color
Free Macrophages
Type of wandering cell
Reinforces fixed macrophages
Mast Cells
Type of wandering cell
Releases chemicals after injury or infection which stimulates local inflammation
Lymphocytes
Type of wandering cell
Increase wherever tissue damage occurs, and some develop into plasmocytes (responsible for production of antibodies, proteins involved in defending body against disease)
Neutrophils and Eosinophils
Type of wandering cell
Attracted to infection or injury
Fibrocytes
Type of fixed cell
Differentiate from fibroblasts
Collagen Fibers
Connective tissue fiber
Long, straight, and unbranched
Reticular Fibers
Thinner than collagen fibers, and they form a branching, interwoven framework that is tough but flexible.
Elastic Fibers
Connective tissue fiber
Branching and wavy, and after stretching up to 150% of their resting length, they recoil to their original dimensions
Mesenchyme
First connective tissue to appear in developing embryo. Contains star-shaped cells that are separated by a matrix that contains very fine protein filaments. This CT gives rise to all other CT’s, including fluid CT’s, cartilage, and bone.
Loose Connective Tissues
A type of connective tissue proper
“Packing material” of the body. These tissues fill spaces between organs, provide cushioning, and support epithelia
Areolar Tissue
A type of loose connective tissue
Locations: Within and deep to the dermis of skin, and covered by the epithelial lining of the digestive, respiratory, and urinary tracts; between muscles; around blood vessels, nerves, and around joints.
Functions: Cushions organs; provides support but permits independent movement; phagocytic cells provide defense against pathogens
Components: collagen fibers, elastic fibers, fibrocytes, and adipocyte
Adipose Tissue
A type of loose connective tissue
Locations: Deep to the skin, esp at sides, buttocks, breasts; padiding around eyes and kidneys
Functions: Provides padding and cushions shocks; insulates (reduces heat loss); stores energy
Components: adipocytes
White Fat
Type of adipose tissue
Provides padding, cushions shocks, acts as an insulator to slow heat loss through the skin, and serves as packing or filler around structures
Brown Fat
Type of adipose tissue
Highly vascularized, and the individual cells contain numerous mitochondria, which gives the tissue a deep, rich color form which the name brown fat is derived
Reticular Tissue
A type of loose connective tissue
Locations: Liver, kidney, spleen, lymph nodes, and bone marrow
Functions: Provides supporting framework
Components: reticular fibers
Dense Connective Tissues (Collagenous Tissues)
A type of connective tissue proper
Most of its volume is collagen fibers.
Dense Regular Connective Tissue
A type of dense connective tissue
Collagen fibers are packed tightly and aligned parallel to applied forces
Dense Irregular Connective Tissue
Type of dense connective tissue
Location: Capsules of visceral organs; periostea and perichondria; nerve and muscle sheaths; dermis
Functions: Provides strength ro resist forces applied from many directions; helps prevent overexpansion of organs such as the urinary bladder.
Components: collagen fiber bundles (w/ no consistent patterns)
Elastic Tissue
Type of dense connective tissue
Locations: Between vertebrae of the spinal column (ligamentum nuchae); ligaments supporting penis; ligaments supporting transitional epithelia; in blood vessel walls
Components: elastic fibers and fibrocyte nuclei
Supporting Connective Tissues
Provides a strong framework that supports the rest of the body (cartilage and bone)
Chondrocytes
Cartilage cells found within the cartilage matrix
Cartilage
A type of supporting connective tissue
Physical property depends on the nature of the matrix. Collagen fibers provide tensile strength, and the combined characteristics of the extracellular fibers and the ground substance give it flexibility and resilience.
Hyaline Cartilage
A type of cartilage
Locations: Between tips of ribs and bones of sternum; covering bone surfaces at synovial joints; supporting larynx (voice box), trachea, and bronchi; forming part of nasal septum
Functions: Provides stiff but somewhat flexible support; reduces friction between bony surfaces
Components: chondrocytes in lacunea, and matrix
Elastic Cartilage
A type of cartilage
Locations: Auricle of external ear; epiglottis; auditory canal; cuneiform cartilages of larynx
Functions: Provides support, but tolerates distortion w/o damage and returns to original shape
Components: chondrocyte in lacuna and elsatic fibers in matrix
Fibrous Cartilage
A type of cartilage
Locations: Pads within knee joint; between pubic bones of pelvis; intervertebral discs
Functinos: Resists compression; prevents bone-to-bone contact; limits relative movement
Components: collagen fibers in matrix and chondrocytes in lacuna
Bone
Osseos tissue. Matrix a mix of calcium salts (strong but brittle) and collagen fibers (weaker but flexible). General organization is lacunae within matrix contain bone cells (osteocytes) and often organized around blood vessels that branch through BONY matrix.
Osteocytes
Bone cells that communicate with blood vessels and with one another through slender cytoplasmic extensions
Canaliculi
Form a branching network for the exchange of materials between blood vessels and osteocytes
Compact Bone
Contains blood vessels trapped within the matrix
Spongy Bone (Cancellous)
Does not contain blood vessels trapped within the matrix
Periosteum
Sheaths almost all bone surfaces, which is composed of a fibrous outer layer and a cellular inner layer. Assists in attachment of a bone to surrounding tissues and to associated tendons and ligaments. The cellular layer functions in bone growth and participates in repairs after an injury
Membranes
Each consists of an epithelial sheet and an underlying connective tissue layer
Mucous Membranes
A type of membrane
Line passageways that communicate w/ the exterior, including the digestive, respiratory, reproductive, and urinary tracts. Forms a barrier that resists the entry of pathogens
Serous Membranes
A type of membrane
Line the subdivisions of the ventral body cavity. Primary function is minimizing friction between these opposing surfaces
Cutaneous Membrane
A type of membrane
The skin; covers the surface of the body. Consists of a keratinized stratified squamous epithelium and an underlying layer of areolar connective tissue reinforced by a layer of dense connective tissue.
Synovial Membranes
A type of membrane
Consists of extensive areas of areolar tissue bounded by an incomplete superficial layer of squamous or cuboidal cells. Joints thatpermit significant movement are surrounded by a fibrous capsule and contain a joint cavity lined by a synovial membrane
Fascia
A general term for a layer or sheet of connective tissue that can be seen on gross dissection
Superficial Fascia or Subcutaneous Layer
A type of fascia
This layer of loose connective tissue separates the skin from underlying tissues and organs. It provides insulation and padding and lets the skin or underlying structures move independently.
Deep Fascia
A type of fascia
Consists of dense regular connective tisse. The fiber organization resembles that of plywood: All the fibers in an individual layer run in the same direction, but the orientation of the fibers changes from one layer to another. This variation helps the tissue resist forces applied from many diff directions.
Subserous Fascia
A type of fascia
A layer of loose connective tissue that lies between the deep fascia and the serous membranes that line body cavities
Muscle Tissue
Specialized for contraction. They are capable of powerful contractions that shorten the cell along its longitudinal axis
Sacroplasm
Cytoplasm of a muscle cell
Sarcolemma
Refers to plasmalemma
Skeletal Muscle Tissue
A type of muscle tissue
Locations: Combined w/ connective tissues and neural tissue in skeletal tissue
Functions: Moves or stabilizes the position of the skeleton; guards entrances and exits to the digestive, respiratory, and urinary tracts; generates heat; protects internal organs
Components: Muscle fiber, striations, nuclei
Multinucleate
Cell containing hundreds of nuclei lying just under the surface of the sarcolemma
Striated Voluntary Muscle
Skeletal muscle fibers appear to have a banded appearance that can have voluntary control their activities
Cardiac Muscle Tissues
A type of muscle tissue
Locations: Heart
Functions: Circulates blood; maintains blood (hydrostatic) pressure
Components: Nucleus, cardiac muscle cells, intercalated discs, striations
Intercarlated Discs
Specialized regions where extensive connections between cardiac muscle cells form
Pacemaker Cells
Specialized cardic muscle cells establish a regular rate of contraction
Striated Involuntary Muscle
Does not provide voluntary control over individual cardiac muscle cells
Smooth Muscle Tissue
A type of muscle tissue
Locations: Found in the walls of blood vessels and in digestive, respiratory, urinary, and reproductive organs
Functions: Moves food, urine, and reproductive tract secretions; controls diameter of respiratory passageways; regulates diameter of blood vessels
Components: Smooth muscle cell and nucleus
Nonstriated Involuntary Muscle
Nervous system does not provide voluntary control over contractions in smooth muscles
Neural Tissue
Specialized for the conduction of electrical impulses form one region of the body to another
Cell Body
Neuron component that contains a large prominent necleus
Dendrites
Site on neuron that receives incoming messages
Axon
Conduct outgoing messages in neuron
Osteoporosis
Reduction in bone strength in women caused by a combination of inactivity, low dietary calcium levels, and a reduction in circulating estrogens
