BIO 201 Chapter 5: The Human Tissues

Tissue

• A group of similar cells and cell products working together to perform a specific role in an organ

Matrix(extracellular material)

• Fibrous proteins

• clear gel: ground substance

Primary germ layers

• tissue layers that is produced by a fertilized egg (Ectoderm,Endoderm,Mesoderm)

Ectoderm

• outer layer

• gives rise to epidermis and nervous system

Endoderm

• inner layer

• mucous membrane

• digestive lining/glands, respiratory tracts

Mesoderm

• middle layer

• cartilage, bone, blood

Histological sections

• Tissue slicked into thin sections

• one or two cells thick

• Ex: Fixative and Stains

Longitudinal Section

• Tissue cut in it long access

Cross/Transverse Section

• Tissue cut perpendicular to long axis of organ

Oblique Section

• Tissue cut at an angle between cross and longitudinal sections

Epithelial Tissue

• Covers body surfaces and lines body cavities

• Constitutes most glands

• Avascular(nourished by underlying connective tissue)

Epithelial Tissue Functions

• Protection:protect deeper tissues from injury and infection

• Secretion:produce and release chemical secretions

• Absorption:absorbs chemicals/nutrients

• Filtration:substances filtered through

• Sensation:sense stimuli

Epithelial Tissue Structure

• Cells are close together

• High rate of mitosis in cells near connective tissue

• Rest on a basement membrane

Basal Surface

• Cell surface facing the basement membrane

Apical Surface

• Surface the faces away from the basement membrane

Lateral Surface

• Between basal and apical surfaces

• side wall

Simple epithelium

• One layer of cells connected to a basement membrane

• simple squamous, simple cuboidal, simple columnar

Simple Squamous Epithelium

• Flat, thin, Scale

• Secretes Substances

• Diffusion/Transport of substances

• Location: Alveoli in Lung

Simple Cuboidal Epithelium

• Square and round

• Absorption and Secretion

• Mucous production and movement

• Location: liver, thyroid, glands

Simple Columnar Epithelium

• Longer than they are wide

• absorption and secretion

• Location: Uterus, GI tract, kidney

Pseudostratified Columnar Epithelium

• Falsely appears to be stratified, but all cells reach the basement membrane

Goblet Cells

• Wine Glass shaped cells

• Mucous Secreting

• Found in simple columnar and pseudostratified tissue

Ciliated pseudostratified columnar epithelium

• Looks stratified but isn’t

• Has cilia and goblet cells

• Secretes and propels nucleus

• Location: Respiratory Tract

Stratified Squamous Epithelium Keratinized

• Multiple layers found on the surface of skin

• Abrasion Resistance

• Soles and Palms

Stratified Squamous Epithelium Non-Keratinzed

• Multiple layers but lacks surface layer of dead cells

• Abrasion resistant

• Tongue, mucus, esophagus

Stratified Cuboidal Epithelium

• Multiple layers of square and round cells

• Secretes sweat, produces sperm, produces ovarian hormones

Stratified Columnar Epithelium

• rare

• Urothelium

• Unique to the urinary tract

• change from round to flat when stretched

Connective Tissue

• Most cells are not indirect contact with each other

• Highly variable vascularity

Connective Tissue Functions

• Binding of Organs

• Support: bones, cartilage

• Physical Protection:cranium, ribs, sternum

• Immune protection: attack foreign invaders

• Movement: bones act as a leverage

• Storage: fat, calcium, phosphorus

• Heat production

• Transport: blood

Fibroblasts

• Fibrous Connective Tissue Cell

• Produce fibers and ground substance

Macrophages

• Fibrous Connective Tissue Cell

• Arise from monocytes

• Phagocytize foreign material

Leukocytes

• Fibrous Connective Tissue Cell

• React against bacteria

Plasma Cells

• Fibrous Connective Tissue Cell

• Synthesize antibodies(proteins)

Mast Cells

• Fibrous Connective Tissue Cell

• Secrete heparin to inhibit clotting and histamine to dilate blood vessels

Adipocytes

• Fibrous Connective Tissue Cell

• Store fat molecules

Collagenous fibers

• tough, flexible, stretch resistant (abundant)

• tendons and ligaments

Reticular Fibers

• Thin and coated with glycoprotein

• framework of spleen and lymphnodes

Elastic Fibers

• Thin and elastic

• stretch and recoil

Components of Fibrous Connective Tissue

• Ground Substance

• Glycosaminoglycans

• Proteoglycans

• Adhesive glycoproteins

Loose Fibrous Connective Tissue

• gel like ground substance surrounding cells

• areolar tissue and reticular tissue

Dense Fibrous connective tissue

• Fibers fill space between cells

• Dense regular tissue and dense irregular tissue

Areolar Tissue

• Loosely organized fibers, abundant blood vessels

• Location: serous membrane, between mm, passageway for nerves

Reticular Tissue

• Forms framework for lymphatic organs, bone marrow, spleen

• mesh of reticular fibers and fibroblasts

Dense regular connective tissue

• Dense, parallel, compressed, wavy tissue

• attach mm to bones and ligaments, hold bones together

Dense irregular connective tissue

• dense, random, few visible cells

• can handle stress, deep layer of skin, capsules around organs

Adipose tissue (white):

• energy, storage, insulation, cushioning, organ packing, body contour, secretes hormones that regulate metabolism

• Fat is recycled continuously

Adipose Tissue (brown)

• In children

• produces heat

• color of the fat comes from blood vessels

Cartilage

• Stiff connective tissue with flexible rubbery matrix

• avascular

• shapes eat, tip of nose, larynx, joints

• heals slowly

Hyaline Cartilage

• clear and glassy appearance

• eases joint movement, holds airways open, moves vocal cords

• Location: joints, ribs, larynx

Elastic Cartilage

• covered with perichondrium

• abundance of elastic fibers

• flexible elastic, supports

• Location: external ear, epiglottis

Fibrocartilage

• large coarse collagen fibers

• resists compression absorbs shock

• Pubic symphysis, menisci

Bone (osseous tissue)

• calcified connective tissue

• skeleton

Compact bone

• calcified connective tissue

• no space, complex arrangement

Central Canal

• where blood vessels and nerves run through the bone

Concentric Lamellae

• Ring like layers of bone surrounding central canal

Osteon

• Central canal and its surrounding lamellae

Osteocytes

• Mature bone cells

Canaliculi

• canals between lacunae

• communication

Lacunae

• holes where osteocytes are located

chondroblasts

• produce the matrix

• “builders”

osteocytes

• mature cells trapped in the lacunae

Spongy bone

• porous appearance, covered by compact bone

• spiny points of bone: trabeculae

• found in heads of long bones and the middle of flat bones

Blood

• fluid, transport cells and dissolved matter from place to place

Plasma

• liquid ground substances in blood

White Blood Cells

• Defend against infection and disease

Red Blood Cells

• Transport 02 and C02

Platelets

• Cell fragments that involve clotting

Nervous Tissue

• Communication by electrical and chemical signals

Neurons

• Nerve cells

• detect, respond, and transmit info

Neuroglia

• glial cells

• protect and assist neurons

Neurosoma

• Cell body of a nerve

• holds nucleus and orgchelles

• controls protein synthesis

Dendrite

• Branched processes that receive signals

Axon

• nerve fiber, sends signals to other cells

Muscular Tissue Function

• contraction, body heat, movement, exert physical force

Skeletal Muscle Tissue

• attach to bone

• voluntary control over skeleton

• striations: light and dark bands

• multiple nuclei

Cardiac Muscle Tissue

• Limited to the heart wall

• Striated, branched, short intercalated discs

• involuntary, one nucleus

Smooth Muscle Tissue

• Fusiform cells, lacking striations

• one nucleus, involuntary

• make up parts of walls of organs

Tight Junction

• Interlocking linkage between two cells

Desmosome

• Patch that holds cells together

• more space than a tight junction

• resists mechanical stress

• hook like

Gap Junction

• Formed by a ring like connexon a channel

• ions and nutrients that pass through the cell

Glands

• Cell that secretes or excrete substances

• composed of epithelial and connective tissue

Secretion

• product useful to the body

Excretion

• waste product

Exocrine Glands

• Have ducts

• sweat, tear glands, pancreas, salivary glands

Endocrine Glands

• No ducts, secrete into blood

• Hormones: chemical messengers

Unicellular glands

• secretory cells found in an epithelium Ex: goblet cells

Capsule

• connective tissue covering exocrine glands

Stroma

• Connective tissue framework, supports and organizes tissue in a gland

Parenchyma

• Cell that Synthesizes and secretes

Serous Glands

• thin, watery

• milk and tears

Mucous glands

• mucin

• goblet cells

Mixed glands

• serous and mucus cell types

• salivary glands in the chin

Eccrine gland secretion

• Release their products by exocytosis

• tear glands, pancreas

Apocrine Gland Secretion

• Lipid droplet covered by membrane and buds from cell surface

• milk secretion by mammary glands

Holocrine gland secretion

• accumulate a product and entire cell disintegrates

• oil glands of scalp and skin

• flands of eyelids

Mucous Membrane

• lines passages that open to the external environment

• absorption, secretion, protection

• Ex: digestive tract

Serous Membranes

• Line internal body cavities

• mesothelium resting on a layer of areolar tissue