Exam 2 Review

What is histology?

Study of tissues

What is a tissue?

Similar cells working together

4 basic tissue classes?

1. Epithelial

2. Connective

3. Muscle

4. Nervous

Fast function for each tissue?

1. Epithelium = Covers

2. Connective = Supports

3. Muscle = Moves

4. Nervous = Controls

What does Epithelial do?

Covers surface, lines cavities, and forms glands

Major Epithelial function?

Protection, absorption, secretion, filtration, diffusion

How are Epithelial cells arranged?

Tightly packed

Does epithelium contain blood vessels?

No, it’s Avascular

How does Epithelium get nutrients?

Diffusion from CT underneath

Apical Surface

Free surface facing outside or a lumen

Lumen

Open space inside a tube or organ

Basal surface

Surface attached to the basement membrane

Basement membrane

Thin layer anchoring epithelium to CT

Tight Junctions

Seal spaces between cells

Microvilli

Increases surface area absorption

Desmosomes

Hold cells together against pulling

Cilia

Move material along the cell surface

Simple Epithelium

One layer; every cell touches the basement membrane

Pseudostratified Epithelium

One layer that looks multilayered, all cells touch basement membrane

Stratified Epithelium

Multiple layers; only the bottom layer touches the basement membrane

Squamous shape

Flat, thin, one layer

Cuboidal shape

About as tall as wide

Columnar shape

Taller than wide

Simple Squamous function

Diffusion and filtration

Simple squamous locations

Alveoli, vessen lining, serous membrane

Endothelium

Simple squamous lining blood and lymph vessels

Mesothelium

Simple squamous lining serous membrane

Simple cuboidal function & location

Secretion and absorption

Kidney tubules and gland ducts

Simple columnar functions

Absorption & secretion

Goblet cells

Epithelial cells that secrete mucus

Where might goblet cells be found?

Intestinal simple columnar & respiratory Pseudostratified epithelium

Ciliates simple columnar location?

Parts of the uterine tubes

Cilia+nuclei at different heights in trachea?

Pseudostratified ciliated columnar

Respiratory pseudostratified functions?

Secretes mucus & moves it with cilia

Where is Keratinized stratified squamous located?

Epidermis

Keratinized stratified squamous functions

Resist abrasion, pathogens, and water loss

Non Keratinized stratifies squamous functions

Protects moist surfaces from abrasion

Rounded surface cells that flatten or stretch?

Transition epithelium

Transitional location and function

Bladder & ureters; stretches

Exocrine glands

Releases product onto a surface, often through a duct

Can a gland be multicellular & exocrine

Yes, these describe different features

Endocrine gland

Releases hormones into fluid & blood; no duct

Tubular vs Alveolar gland

Tubular = Tube-shaped

vs

Alveolar = sac-shaped secretory part

Simple vs compound duct

Simple = unbranched

Vs

Compound = branched

Tubuloalveleolar

Both tube and sac secretory parts

Merocrine secretion

Exocytosis; cells stays intact

Apocrine secretion as a general mode?

Apical portion pinches off

Holocrine secretion

Whole cells break apart to release product

Cutaneous membrane

Skin; epithelium over CT

Sebaceous gland secretion mode?

Holocrine

Cutaneous membrane

Skin; epithelium over CT

Serous membrane

Lines closed body cavities; mesothelium at surface

Mucous membrane

Lines passages open to the exterior

Main CT functions

Bind, support, protect, insulate, store

3 CT components

1. Cells

2. Fibers

3. Ground substances

Extracellular matrix

Fibers plus ground substances outside the cells

How does CT differ from Epithelium?

More matrix between cells

Does CT always have vessels?

No, blood supply varries

Which is avascular? Bone or Cartilage

Cartilage

Collagen fibers

Strength, resist pulling

Why does cartilage heal slowly?

Nutrients must diffuse through matrix

Elastic fibers

Stretch & recoil

Reticular fibers

Fine supportive network

Fibroblasts

Builds fibers & ground substance

Fibrocyte

Maintains existing matrix

Mast cells

Releases histamine in inflammation

Adipocytes

Stores fat

Macrophage

Engulfs debris & microbes

Plasma cell

Produces antibodies

Areolar slide clues?

Scattered cells, thick collage, thin elastic fibers, open spaces

Loose open weave with several fiber types?

Areolar; under epithelium, wraps & cushions

Adipose locations

Underskin, around kidneys & eyes, abdomen & breasts

Adipose location

Under skin; around kidneys & eyes

Reticular tissue location & function

Lymph nodes, spleen, bone marrow

Supportive framework

Dark branching mesh full of immune cells?

Reticular CT

Parallel collagen bundles

Dense regular, tendons & ligaments, one direction pull

Collagen bundles pointing many ways?

Dense irregular, reticular dermis, multidirectional strength

Many wavy elastic fibers?

Elastic CT, artery walls, bronchial tubes

Stretch & recoil

Cartilage cells in a small space

Chondrocytes in Lacunae

Chondroblasts

Bulds cartilage matrix

Hyaline cartilage slide cue?

Smooth, glassy matrix, fingers hard to see

Hyaline function

Flexible support, cushion joints

Elastic cartilage slide cue

Lacunae + visible elastic fibers

Fibrocartilage slide cue?

Chondrocytes among thick collagen bundles

Fibrocartilage functions

Absorbs shock; resist compression

Hyaline location

Nose, trachea, rib cartilage

Most common cartilage?

Hyaline

Elastic cartilage location & function

External ear, epiglottis

Flexible support

Fibrocartilage location

Intervertebral discs, pubic symphysis, knee menisci

Perichondrium

CT covering around most cartilage ; nourishes it

Osteoblast vs osteoclast

Osteoblasts=build bone

Osteoclasts=breaks bones

Why is bone hard?

Mineral salts in matrix

Blood extracellular matrix

Fluid plasma

3 muscle types

1. Skeletal

2. Cardiac

3. Smooth

Osteocyte

Mature bone cell maintaining matrix

Bone vs Cartilage blood supply?

Bone = vascular

Cartilage = Avascular

Bone functions

Support, protection, movement, minerals, blood cell formation

Main function: transport

Contractile proteins

Actin & myosin

2 layers of skin itself

Epidermis & dermis

Epidermis tissue types?

Keratinized stratified squamous epithelium