Major Tissue Major Tissue TypesTypes

• Epithelial Tissue• Connective Tissue• Muscle Tissue• Nervous Tissue

Tissues are groups of cells with a common function.

Germ LayersGerm Layers

1.Endoderm2.Mesoderm3.Ectoderm

All tissue types are derived from 3 primary germ layers

1. Endoderm- internal lining of the gut internal lining of the gut and respiratory pathways, liver, and respiratory pathways, liver, pancreaspancreas

2. Mesoderm- notochord (in chordates), notochord (in chordates), dermis, blood vessels, heart, bones, dermis, blood vessels, heart, bones, cartilage, musclecartilage, muscle

3. Ectoderm- hair, nails, epidermis, hair, nails, epidermis, brain, nervesbrain, nerves

Tight Junction • fluid tight seal • prevents fluid from leaving a cavity

  Anchoring Junction (adherens, desmosome &

hemidesmosome) • tissues that stretch, ex. Heart muscle

  Gap Junction

• passage of chemical & electrical signals

Contact points between the plasma membrane of tissue cells.

Gap Junction

Hemidesmosome Desmosome Adherens

Tight Junction

Epithelia comes in 2 forms:1. Glandular epithelia 2. Membranous epithelia

Functions:• Protection• Absorption• Filtration• Excretion• Secretion• Sensory reception

Multicellular exocrine gland: most have supportive connective tissue, secretory unit, blood supply, nerves

• Merocrine- pancreas, sweat glands, salivary• Holocrine- sebaceous• Apocrine- sweat glands, mammary glands

ducted glands

Merocrine gland Holocrine gland

Unicellular exocrine gland: single cells scattered in an epithelial sheet amid cells w/other functions

Goblet cells

Lg intestine Sweat glandsGastric Sebaceous

Cowper’sMammary Acinar of pancreas

Liver

Secretes product directly directly in blood

Secretes product through duct

• Simple Squamous Epithelium• Simple Cuboidal Epithelium• Simple Columnar Epithelium• Stratified Epithelium• Pseudostratified Columnar Epithelium• Transitional Epithelium

Function: gas exchange in lungsLocation: lines blood vessels, lymph vessels and various membranes within the thorax and abdomen

Frog skin

Function: secretion and absorption

Location: kidney tubules

Mammalian kidney

Function: protection, secretion and absorption (associated w/goblet cells-exocrine) Location: lines uterus and digestive tract

1. Smooth muscle (long. layer) 2. Smooth muscle (circ. layer) 3. Simple columnar epithelium 4. Goblet cell 5. Lumen of the intestine

Cross section of small intestine

Function: protects underlying cells from harmful env. effects

Location: covers skin, lines mouth and throat, vagina, and anal canal

1. Stratified squamous epithelium 2. Lumen of the esophagus 3. Connective tissue

Cross section of esophagus

cornified layer of dead cellscornified layer of dead cells

stratified squamous epithelium

stratified squamous epithelium

goblet cellgoblet cell

Function: secretion and propulsion of mucus

Location: lines respiratory and reproductive system

Function: protection and secretion

Location: rare in body, small amount in male urethra and in large ducts of some glands

Function: stretches

Location: lines ureters, bladder and part of urethra

• Loose Connective TissueLoose Connective Tissue• Dense Connective TissueDense Connective Tissue• Adipose TissueAdipose Tissue• CartilageCartilage• BoneBone• BloodBlood

Functions:1. Connects body parts2. Protection3. Insulation4. Transport substances

Common characteristics:1. All originate from mesenchyme2. Well vascularized3. Extracellular matrix

Three main elements:1. Ground substance2. Fibers3. Cells

Ground Substance:• Water• Polysaccharide• Protein

Fibers:• Reticular• Elastic• Collagen

Cell Types:• Fibroblast• Chondroblast• Osteoblasts• Macrophages• Plasma Cells • Mast Cells• Adipocytes• White Blood Cells

Embryonic Connective Tissue

Loose Loose ConnectiveConnective Tissue Tissue(areolar)(areolar)

1. Collagen fiber2. Elastic fiber

• Subcutaneous layer underlying tissues & organs

Location: lymphoid organs- spleen, lymph nodes, bone marrow

• Stores triglycerides• Good insulator• Supports & protects organs

• Forms tendons & ligaments

Cross section of tendon

• In fascia and periosteum of bone

Dermis of skin

Costal cartilage between ribs

chondrocytes in lacunaechondrocytes in lacunae

elastic fiberselastic fibers

chondrocyte chondrocyte in lacunain lacuna

collagen collagen fibersfibers

Invertebral discs, pubic symphysis, disks of knees

compact bone

spongy bone

osteocytes osteocytes in lacunaein lacunae

central central canalcanal

canaliculi canaliculi in matrixin matrix

erythrocyteserythrocytes

leukocytesleukocytes

• Skeletal Muscle Tissue• Smooth Muscle Tissue• Cardiac Muscle Tissue

Biology 100Biology 100Human BiologyHuman Biology

Inquiry

1. What is the difference between the three types of muscle tissue?

2. What type of epithelia tissue has many layers of flattened cells?

3. What layer in the epidermis are new skin cells produced?

4. What is the difference between endocrine and exocrine glands?

5. Which organ system includes the thymus and pancreas?