Lecture Week 5 Flashcards
What is Histology?
Study of the structure and function of tissues
What are the tissue types?
Epithelium, Connective, Muscle, Neural
What does Epithelial Tissue do?
-Covers exposed surfaces
-Lines internal passageways and chambers
-Forms secretory glands
What does Connective Tissue do?
-Contracts to produce movement
What does Neural/Nervous Tissue do?
-Conducts electrical impulses
-Carries information
What are characteristics of Epithelium?
-Covers organs and body, lines body cavities and hollow organs
-Has free surface and basement membrane
-Connective tissues lie below basement membrane
-Non-vascular (no blood vessels running through)
-Little intercellular material
-Rapid healing, frequent cell replacement
What are the functions of Epithelium?
Absorption, secretion, excretion, diffusion, protection, distension (stretching)
How is Epithelium Classified?
By the stratification (layering) and cell shape
What are the 4 layers called of Epithelium?
-Simple: 1 cell layer thick
-Stratified: 2 or more cell layers thick
-Pseudostratified: falsely layered, looks like more than one layer but is only one layer
-Transitional: layers depend on tension (stretching)
What does squamous mean?
Flat
What does cuboidal mean?
Tall as it is wide
What does columnar mean?
Taller than wide
What does basement membrane lie between?
Epithelial and connective tissue
What do microvilli do?
Promote absorption
Simple Squamous Epithelium
-Lines alveoli, forms capillary walls, lines blood and lymph vessels, covers body cavity membranes
-Functions: diffusion, filtration, decrease friction
Stratified Squamous Epithelium
-Surface of skin, linings of oral cavity, vagina, anal canal, and part of the pharynx
-Functions: Protection
-Features: may be nonkeratinizing or keratinizing
Simple Cuboidal Epithelium
-Covers ovaries, lines kidney tubules and ducts of many glands
-Functions: Absorption, secretion, excretion
Stratified Cuboidal Epithelium
-Linings of larger ducts of mammary glands, sweat glands, salivary glands, and pancreas
-Functions: protection, secretion
Transitional Epithelium
-Lining of urinary bladder, ureters, part of urethra
-Functions: protection, distension
Simple Columnar Epithelium
-Lines uterus, stomach, intestines, uterine tubes
-Functions: secretion, absorption, protection, production of movement
-Features: may have cilia for movement or microvilli for absorption, mucus secreting goblet cells
Stratified Columnar Epithelium
-Lining ductus deferens, part of male urethra, part of pharynx
-Functions: protection, secretion
Pseudostratified Columnar Epithelium
-Lines respiratory passageways
-Functions: protection, secretion, production of movement
-Features: may be ciliated with mucus secreting goblet cells
What are the two types of glands?
-Exocrine and Endocrine
What do exocrine glands do?
Secrete onto a surface
What do endocrine glands do?
Secrete directly into blood or tissue fluid
What are the characteristics of typical connective tissue?
-Abundant intercellular material called matrix, matrix contains ground substance and fibers, generally vascular
What do fibroblasts produce?
Fibers
What do macrophages in?
Phagocytosis
What are adipocytes in?
Adipose
What are chondrocytes in?
Cartilage
What are osteocytes in?
Bone
How to describe collagenous fibers?
Produce collagen protein, thick, strong
How to describe elastic fibers?
Produce elastin protein, flexible, recoil
How to describe reticular fibers?
Collagen protein, thin, branch
What are the ground substances?
Gel-like, reduced, firm-solid, hard-solid, fluid
What is the matrix made up of?
Fibers and ground substance
Areolar Tissue
-Below skin and below the basement membrane of most epithelia
-Function: binds structure together
Adipose
-Beneath skin, between muscles, around kidneys and heart, behind eyes, in abdominal membranes
-Function: adipocytes accumulate triglycerides for energy storage, insulation, and protection
Reticular Connective
-Liver, spleen, lymph nodes
-Function: Structural support
Dense Connective
-Regular (tendons, ligaments), Irregular (dermis of skin)
-Function: provides strength,
-Features: slow to heal bc mainly nonvascular
Elastic Connective
-Walls of larger arteries, heart chambers, larger airways, between vertebrae
-Function: Provides strength with elasticity
Blood
-Cardiovascular system
-Function: transport, protection from infection, prevention of blood loss
-Features: formed elements in plasma
Hyaline Cartilage
-Non-vascular, most abundant in body
-Ends of bones, tracheal rings, bone models in fetus and child
-Functions: support, bone development
-Features: chondrocytes occupy lacunae, tissue is nonvascular
Elastic Cartilage
-External ears, part of larynx
-Function: support with elasticity
Fibrocartilage
-Intervertebral disks, menisci of knee joints
-Function: Support with increased strength and durability
Bone
-Skeleton
-Function: Support, protection, attachment sites for muscles, mineral storage
-Features: osteocytes occupy lacunae,
Tissue Comparisons (Location, Intercellular Material, Vascularization)
Epithelia: covers surfaces and line cavities (have free surface), almost no intercellular material, no vascularization
Connective: fills spaces, abundant matrix, extensive vascularization
Tendons
Structures that anchor muscles to bones
Ligaments
Structures that hold bones together at a joint
Types of Membranes
Serous, mucous, synovial, cutaneous
Serous Membrane
Line and cover organs within the ventral cavity, serous fluid functions as lubricatioin, in simple squamous, areolar
Mucous Membrane
Line cavities that open to the outside of the body, mucus, various epithelia and areolar
Synovial Membrane
Line cavities of freely moveable joints, synovial fluid to cushion, areolar and adipose
Cutaneous Membrane
Covers the body outer surface, secrete sweat and sebum, in stratified squamous epithelium, areolar, irregular dense connective
What are the organs of the Integumentary System?
Cutaneous membrane (biggest organ overall is skin), hair follicles, sebaceous glands, sweat glands, nails
Functions of Integumentary System
-Protect underlying tissues and organs
-Excrete salts, wastes, water
-Maintain body temp
-Produce melanin - protects underlying tissue from ultraviolet radiation
-Produce keratin - serves as water repellant
-Store lipids
-Detect touch, pressure, pain, etc. and relay to nervous system
Epidermis
Superficial layer of the skin
What kind of epithelium forms epidermis?
Stratified squamous keratinizing epithelium
How thick is the epidermis?
0.08-0.5 mm thick
Stratum Basale
Single layer of cuboidal or columnar stem cells
Stratum Spinosum
8-10 layers of flatter cells, some of which are stem cells
Stratum Granulosum
Missing in thin areas
Stratum Lucidum
Only in palms and soles
Stratum Corneum
15-30 layers of flattened, dead, keratinizing cells
What are the cell types?
Keratinocytes - produce keratin protein
Melanocytes - produce melanin protein
Dendritic cells - protect against microorganisms and superficial cancers
Keratinization
Keratinocytes produce and accumulate keratin and die as they are pushed away from blood vessels and towards body surface
Where are epidermal ridges present to increase friction?
Hands and feet
How does a person get their color of skin?
Results from specific molecules that are present in the skin
How many pigments are responsible for skin color?
3
What are the three pigments?
Melanin, Hemoglobin, Carotene
Melanin
Brown, yellow-brown, black
Produced by melanocytes in epidermis
Production promoted by UV radiation, protects DNA molecules in deeper cells
Hemoglobin
Bright red - carrying oxygen gas
Dark red - not carrying oxygen gas
Carotene
Orange-yellow
From vegetables can accumulate in epidermis
