Lesson 3 Tissues Flashcards
What is tissue repair?
Substitution of viable cells for dead cells by regeneration or replacement.
Define regeneration in the context of tissue repair.
New cells of same type are produced; function is restored.
What does replacement mean in tissue repair?
New type of tissue develops, resulting in scar and loss of function.
What are the three classifications of cells based on their ability to regenerate?
- Labile
- Stable
- Permanent
What type of cells are classified as labile?
Capable of mitosis through life; examples include skin, mucous membranes, hemopoietic tissue, lymphatic tissue.
Describe stable cells.
No mitosis after growth ends, but can divide after injury; examples include liver, pancreas, endocrine cells.
What are permanent cells?
If killed, replaced by a different type of cell; limited regenerative ability; examples include nervous, skeletal, and cardiac muscle.
What are the two types of embryonic connective tissue?
- Mesenchyme
- Mucous CT
What is mesenchyme?
Source of all adult connective tissue; forms primarily from mesoderm.
What is the composition of areolar connective tissue?
Loose packing material containing collagen, reticular, elastic fibers and five types of cells.
What are the predominant cells in adipose tissue?
Adipocytes.
What distinguishes brown adipose tissue from yellow adipose tissue?
Brown is found only in specific areas; yellow is more abundant and has a wide distribution.
What is the function of reticular tissue?
Forms superstructure of lymphatic and hemopoietic tissues.
What are the three major components of the extracellular matrix?
- Protein fibers
- Ground substance
- Fluid
Identify the three types of protein fibers in connective tissue.
- Collagen
- Reticular
- Elastic
What are the functions of connective tissue?
- Enclose organs
- Connect tissues
- Support and movement
- Storage
- Cushion and insulate
- Transport
- Protect
What are the roles of fibroblasts, fibrocytes, and osteoclasts?
- Fibroblasts: create the matrix
- Fibrocytes: maintain the matrix
- Osteoclasts: break the matrix down for remodeling
True or False: Adipose cells are common in some tissues but rare in others.
True.
What is the primary function of mast cells?
Release heparin, histamine, and proteolytic enzymes in response to injury.
What is the difference between fixed and wandering macrophages?
- Fixed: stay in position in connective tissue
- Wandering: move by amoeboid movement
What is primary union in skin repair?
Edges of wound are close together; wound fills with blood, clot forms, and inflammatory response occurs.
What is the significance of granulation tissue in wound healing?
Replaces clot; composed of fibroblasts, collagen fibers, capillaries.
What is the structure of hyaline cartilage?
Large amount of collagen fibers evenly distributed in proteoglycan matrix; chondrocytes in lacunae.
Where is fibrocartilage typically found?
In areas of body where a great deal of pressure is applied, such as the knee, jaw, and between vertebrae.
Define simple squamous epithelium.
Single layer of flat cells.
What are the functions of simple cuboidal epithelium?
- Secretion and absorption in the kidney
- Secretion in glands
- Movement of mucus in bronchioles
What characterizes stratified squamous epithelium?
Multiple layers of cells that are cuboidal in the basal layer and flatten toward the surface.
What is the role of chemical mediators in inflammation?
Stimulate pain receptors and increase blood vessel permeability.
What is edema?
Swelling due to fluid leaving capillaries during inflammation.
What is the function of gap junctions?
Aid intercellular communication and coordinate function of cardiac and smooth muscle.
What are the locations where keratinized epithelium can be found?
Mouth, throat, larynx, esophagus, anus, vagina, inferior urethra, and cornea.
What is the structure of keratinized epithelium?
Multiple layers of cells that are cuboidal in the basal layer and progressively flatten toward the surface. Surface cells are dead.
What are the functions of keratinized epithelium?
Protection against abrasion, caustic chemicals, water loss, and infection.
What are the functions of cell connections?
Form permeability layer, bind cells together, provide mechanism for intercellular communication.
Name the types of cell connections.
- Desmosomes
- Hemidesmosomes
- Tight junctions
- Adhesion belt
- Gap junctions
What are the characteristics of smooth free surfaces of epithelium?
Reduce friction.
What is the purpose of microvilli on epithelial surfaces?
Increase surface area for absorption or secretion.
What is the function of cilia on epithelial surfaces?
Move materials across the surface.
Where is simple columnar epithelium located?
- Glands
- Some ducts
- Bronchioles of lungs
- Auditory tubes
- Uterus
- Uterine tubes
- Stomach
- Intestines
- Gallbladder
- Bile ducts
- Ventricles of the brain
What is the structure of simple columnar epithelium?
Single layer of tall, narrow cells; some have cilia or microvilli.
What are the functions of simple columnar epithelium?
- Movement of particles out of the bronchioles by ciliated cells
- Aids in the movement of oocytes through the uterine tubes
- Secretion by glands of the stomach and intestine
- Absorption by cells of the intestine
Where is transitional epithelium located?
Lining of urinary bladder, ureters, and superior urethra.
What is the structure of transitional epithelium?
Stratified; cells change shape depending upon the amount of distention of the organ.
What are the functions of transitional epithelium?
Accommodates fluctuations in the volume of fluid in an organ or tube; protection against the caustic effects of urine.
What are the functional characteristics of simple layering in epithelium?
Allows diffusion of gases, filtration of blood, secretion, absorption.
What is the protective function of stratified layering in epithelium?
Protection, particularly against abrasion.
What is the role of squamous cell shape in epithelium?
Allows diffusion or acts as a filter.
What do cuboidal and columnar cell shapes in epithelium indicate?
Secretion or absorption; may include goblet cells that produce and secrete mucus.
Where is pseudostratified columnar epithelium located?
- Lining of nasal cavity
- Nasal sinuses
- Auditory tubes
- Pharynx
- Trachea
- Bronchi of lungs
What is the structure of pseudostratified columnar epithelium?
All cells reach basement membrane; appears stratified because nuclei are at various levels.
What are the functions of pseudostratified columnar epithelium?
- Synthesize and secrete mucus onto the free surface
- Move mucus (or fluid) that contains foreign particles over the free surface and from passages
