Ch.4 - Tissues (Anatomy)

DT = defining trait (for ID practice) + goes up to blood tissue for now

Four Main Types of Tissues

Epithelial (covering), Connective (support), Muscle (movement), Nervous (control)

Epithelial Function

• protection

• diffusion

• absorption/secretion

• transport/filtration

• forms slippery surfaces (i.e: cavities)

Epithelial

-densely packed w/cells

cell junctions in between cells

no blood cells → gets nutrients from underlying connective tissue @ lamina propria

Lamina Propria significance

carries blood supply to the epithelium + holds cells in place and binds them to smooth muscle below

Naming system for Tissues

1st name = # of layers (simple: 1 or stratified 2/+)

last name = desc. shape apically (top)

Shapes of Cells (last name description)

Squamous, Cuboidal, Columnar

Squamous Cells

width > height (plate-like) + flattened, disc nuclei

Cuboidal

width = height, circular nuclei

Columnar

height > width + oval/elongated nuclei

Simple Squamous Epithelium Cells

Function: secretes serous fluid → serous cavity + helps w/ passive diffusion, filtration

@ alveoli of Lungs, heart, blood + lymphatic vessels

Simple Cuboidal Epithelium Cells

Function: secretion/absorption

@ kidney tubules, ovary surface, secretory portions at small glands

DT: two rings, outer filled with nuclei

Simple Columnar Epithelium Cells (Ciliated)

Function: propels mucus/reprod. cells +secretion of mucus

@ lining of small bronchi, uterine tubes, uterus

Simple Columnar Cells Epithelium (Non-Ciliated)

Function: absorption/secretion by using microvilli to UP surface area for nutrients

@ lines digestive tract, gall bladder, ducts

Goblet Cell

@ simple epithelia + pseudostratified epithelia

Function: protect epithelium, secret mucin (that’ll → mucus) and trap dust

Pseudostratified Columnar Epithelial Cells

*appears to be multiple kinds of cells, but is actually just columnar nuclei seen at different levels

Function: same as columnar epithelial cells

non-ciliated: @ sperm-carrying + large glands’ ducts

ciliated: lines trachea and most of upper respiratory tract

Stratified Epithelia Properties

• 2/+ layers of cells

• name based on shape of cell at APICAL layer

• regenerate from basal layer

• major role protection

Stratified Squamous Epithelium (Keratinized)
*surface cells are dead and full of Keratin

Function: protective protein of Keratin + waterproof

@ Epidermis
DT: tissue appears like an ocean wave + layers of dead skin on top w/o nuclei (b/c dead)

Stratified Squamous (Non-keratinized)

Function: moist lining of body openings

@ vagina, mouth, esophagous

DT: wavy, thin cells on top with cuboidal cells at the basal layer

Stratified Cuboidal Epithelium

Function: protection

@ mammary/salivary/sweat glands
*note the multiple layers in close prox.

Stratified Columnar Epithelia

Function: protection + secretion
@ male urthera and large ducts of some glands (rare)
*DT: basal levels usually cuboidal w/ superficial cells looking columnal

Transitional Epithelium

Function: stretches readily for distension
@ uterus/bladder
DT: bulbous cells on top of basal columnar cells

Types of Connective Tissue

CT Proper, Cartilage, Bone Tissue, Blood
*cells seperated by large amt. of extracellular matrix except blood, which doesnt have a matrix

(Extracellular) Matrix

made of ground substance (holds tissue interstitial fluid so gel-like) and fibers

*Blood has plasma engulf it instead

Structural Fibers found in CT

collagen , reticular, elastic

Collagen Fibers

function: strongest of all fibers, resists tension and prevents scurvy
structure: a network of crosslinks made of Vitamin C

Reticular Fibers

function: covers/support structures
structure: bundles of special collagen
* NOT VISIBLE UNDER MIROSCOPY BUT IS PRESENT

elastic fibers

made of elastin
function: recoils after stretching

Connective Tissue Proper’s Subclasses

Loose Connective Tissue: areolar, adipose, reticular
Dense Connective: Irregular, regular, elastic

Connective Tissue Proper:

cells: fibroblast, fibrocytes, fat cells
contains all 3 fiber types
function: binding tissue + resists tension

Areolar CT:

function: helps immune cells like WBC + wraps/cushions organs + holds interstitial fluid

@ underneath epithelia (highly vasculized to give nutrients and help excrete waste)

DT: elastic + collagen fibers all over

Adipose Tissue

Function: warmth + reserve food storage + protects organs and storing energy

@ hypodermis (fatty layer) + kidney, eyeballs, w/in abdomen and breasts

DT: fatass cells pushing their nuclei to the edges

Reticular CT

structure: network of reticular fibers in loose ground substance

function: fibers form soft internal skeleton to support other cell types

@ lymphoid organs (bone marrow, spleen, etc.)

DT: hella dots together with cells loosely together

Dense Irregular Tissue:

function: withstand tension + structural strength

@ dermis of skin + submucosa of digestive tract

DT: collagen fibers in different directions + nuclei (dyed in purple) more visible comapred to dense regular tissue

Dense Regular Tissue:

Function: reduce tension in ONE direction

@ tendons, fascia, aponeuroses, wrap skeleton like shoulder joint

DT: fibroblasts in 1 direction

Dense Elastic:

Function: recoil tissue → pulsatile blood flow + help w recoil of lunges while breathing

@ walls of bronchial tubes + large arteries

DT: close together squiggly lines, much darker than other CT

Cartilage:

structure: firm/flexible tissue + NO blood vessels/nerves + matrix made of 80% water

function: water resists compression

2* = Chondrocyte (no longer actively reprod. cells)

Hyaline Cartilage:

Function: supports/reinforces/cushions + resists compression NOT tension

@nose +trachea

DT: looks like model of ribsomal subunits together, tissue overall looks like frosted glass

Elastic Cartilage:

*has more elastin than Hyaline cartilage

Function: maintain shape w/flexibility

@ helps external ear; epiglottis

DT: looks like Tom and Jerry steak

Fibrocartilage

Function: absorbs shock

@ between intervertebral discs, pubic symphsis,

DT: rows of chondrocytes

Bone Tissue:

Function: acts as levers for the muscles to pull at + stores calcium/minerals/fat + marrow inside for hematopoiesis

Structure: hard, calcified matrix with hella collagen fibers and wall vassalized with osteocytes that lie in lacunae

DT: looks like tree rings

Blood Connective Tissue:

Structure: ANUCLEAR and NO ORGANELLES
Function: transport respiratory gases/nutrients/waters/etc.

@ blood vessels


DT: model is literally one big circle inside a circle