Tissues

All human body cells belong to one of these tissues:◦ epithelial tissue◦ connective tissue◦ muscle tissue◦ nervous tissue

The Four Tissue Types

Epithelial Tissue

Epithelial tissue lines every body surface and all body cavities.

Organs are lined on the outside and inside by epithelial tissue.

The majority of glands are derived from epithelial tissue.

Identified by cell shape and layers

Epithelial Tissue

Anatomy: Single layer of flat cells

Function: Rapid diffusion, filtration, some secretion (Serous membrane)

Location: Alveoli, heart chamber lining, BV’s, Serous membrane of body cavities

Simple Squamous Epithelium

Anatomy: Single layer of cube-shaped cells

Function: Absorption and secretion

Location: Thyroid gland, kidney tubules, ducts of most exocrine glands, surface of ovary

Simple Cuboidal Epithelium

Anatomy: Single layer of cells that are taller than they are wide. Microvilli & Goblet cells.

Function: Absorption, secrete mucin

Location: Digestive tract lining. (No goblets in stomach)

Non Ciliated: Simple Columnar Epithelium

Anatomy: Single layer of cells that are taller than they are wide. Cilia & Goblet cells

Function: secrete mucin, movement of mucous and particles (ex: eggs)

Location: uterine tubes, larger bronchioles

Ciliated Simple Columnar Epithelium

Anatomy: Multiple layers of flattened cells◦ Keratinized: no nuclei ◦ Nonkeratinized: Nuclei

Function: Protect underlying tissue

Location:◦ Keratinized: Epidermis◦ Nonkeratinized: Oral cavity,

pharynx, esophagus, anus, Vagina

Stratified Squamous Epithelium

Anatomy: Multiple layers of cube-shaped cells Function: Protection and secretion Location: large ducts or exocrine glands and

parts of male urethra

Stratified Cuboidal Epithelium

Anatomy: Multiple layers of cells that are taller than they are wide

Function: protection and secretion

Location: RARE; some exocrine glands and male urethra

Stratified Columnar Epithelium

Anatomy: Single layer of columnar epithelial cells but layered appearance of nuclei◦ Ciliated has goblet cells

Function: Protection◦ Ciliated: secrete mucin and

cause movement Location:

◦ Cilitated: respiratory tract (nasal cavity bronchi)

◦ Non-ciliated: epididymus and male urethra

Ciliated and Non-ciliatedPseudostratified Columnar Epithelium

Anatomy: polyhedral

Function: distension and relaxation

Location: urinary bladder, ureters, and part of urethra

Transitional Epithelium

Muscle TissueSupportive

Classification of MuscleCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Structure

Function

Location Location

Function

Structure

Skeletal muscle Heart wall

Nuclei

Striations

LM 500x

Nuclei

Striations

Skeletal musclefiber

Intercalateddiscs

Cardiacmuscle cell

Striations

NucleiSkeletal musclefiber

Intercalateddiscs

Nuclei

Striations

Cardiacmuscle cell

Table 4.14 Muscle Tissue

(a) Skeletal Muscle Tissue (b) Cardiac Muscle Tissue

Fibers are long, cylindrical, striated, parallel, andunbranched; fibers are multinucleated with nucleialong periphery

Moves skeleton; responsible for voluntary bodymovements, locomotion, heat production

Attaches to bones or sometimes to skin (e.g., facialmuscles); also found in the voluntarysphincters—lips, urethra, anus

Cells are short, bifurcated, and striated, with oneor two centrally located nuclei; intercalated discsbetween cells

Involuntary contraction and relaxation pump bloodin heart

Heart wall (myocardium)

a:© The McGraw-Hill Companies, Inc./Photo by Dr. Alvin Telser; b,c: © Victor Eroschenko

Muscularis ofsmall intestine

Nuclei ofsmoothmuscle cells

Nuclei ofsmoothmuscle cells

Structure

Function

Location Walls of hollow internal organs, such asvessels, airways, stomach, bladder, uterus

Cells are fusiform (spindle-shaped), short,nonstriated, and contain one centrallylocated nucleus

Involuntary movements and motion; movesmaterials through internal organs

(c) Smooth Muscle Tissue

Attached to bones of skeleton and some skin

Cells (muscle fibers) are:◦ cylindrical and long (some as long as whole

muscle)◦ multinucleated◦ striated (striped internal appearance) and

voluntary Contraction causes movement of skeleton

or skin

Skeletal Muscle

Found in the wall of the heart (myocardium) Cells are:

◦ Y-shaped, shorter than skeletal fiber cells◦ striated and involuntary◦ attached by strong gap junctions called

intercalated discs: allow rapid passage of electrical current

Contraction causes movement of blood

Cardiac Muscle

Found in walls of most internal organs◦ stomach, intestines, urinary bladder

Cells are:◦ relatively short, wide in the middle, and tapered

at the ends◦ involuntary and non-striated

Contraction causes movement of food, blood, sperm

Smooth Muscle

Connective TissueProper

CT types present after birth can be classified into three broad categories:◦ CT proper◦ Supporting CT◦ Fluid CT

Classification of Connective Tissue

Body’s packing material, in spaces around organs; there are three types: Areolar CT: fibroblasts, collagen, and

elastic fibers; distorted without damage; found subcutaneous to skin

Loose Connective Tissue

Adipose CT: known as “fat,” comprised mainly of adipocytes (fat cells) and very little else

Loose Connective Tissue

Reticular CT: contains reticular fibers, fibroblasts, and leukocytes; found in spleen, lymph nodes, and bone marrow

Loose Connective Tissue

Strong, fibers (mostly collagen) packed tightly together; there are three types: 1. Dense regular CT

◦ collagen fibers aligned parallel to force◦ tendons (attach muscle to bone) and

ligaments (attach bone to bone)

Dense Connective Tissue

2. Dense irregular CT

◦ bundles of collagen fibers in many directions

◦ In deep portion of the skin (dermis) and capsules around organs (liver, kidney, and spleen)

Dense Connective Tissue

Elastic CT◦ predominant elastic fibers provide ability to

stretch and recoil◦ found in the vocal cords and large/medium

arteries

Dense Connective Tissue

Connective TissueSupportive

There are three types of cartilage: 1. Hyaline cartilage

◦ most common but the weakest◦ In fetal skeleton, ends of bones that articulate

with each other, in trachea, larynx, and nose

Cartilage

2. Fibrocartilage ◦ densely interwoven collagen fibers= to the

durability◦ In intervertebral disc, pubic symphysis, and the

menisci of the knee acts as shock absorber

Supporting Connective Tissue

Elastic cartilage◦ elastic fibers are main feature◦ found in epiglottis and external ear

both structures need to bend and snap back to original form

Supporting Connective Tissue

Nervous Tissue

Contains two types of cells:◦ Neurons: nerve cells that are

capable of initiating and conducting electrical activity throughout the body

◦ Neuroglia: cells that support the neurons

Function is communication and control of body functions

Nervous Tissue

NeuronCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Axon

Dendrite

Cell bodyof neuron

Nuclei ofglial cells