S&F Lab 2 Quiz

Tissues definition

Groups of similar cells working together to perform a specific function

Types of tissue

• Epithelial

• Connective

• Muscle

• Nervous

Epithelial tissue characteristics

• Avascular

• Innervated

• Tightly packed cells with minimal extracellular matrix

• Highly regenerative

• Has apical and basal sides

Avascular definition

Has no blood vessels

Innervated definition

Has a nerve supply

Apical side

Faces external environment or organ/ cavity in human

Basal side

Faces basement membrane

Where does epithelial tissue line

• outer layer of skin/ body

• Inner layer of organs

Locations of epithelial tissue

• Skin

• Lines body cavities

• Lines organs

• Glands

• Serous membranes

Exocrine glands

Produce products released through a ducts onto a body’s surface or in a cavity

• sweat, oil, saliva

Endocrine glands

Releases hormones into the bloodstream

Structures of epithelial tissues

• Simple

• Stratified

Simple structure of epithelial tissues

• 1 cell layer

• Attached to basement membrane

Pseudostratified structure of epithelial tissues

• 1 Cell layer

• Looks stratified, but isn’t

• Contains cilia on apical side

Stratified structure of epithelial tissue

• Multiple cell layers

Epithelial cell shapes

• Squamous

• Cuboidal

• Columnar

Squamous epithelial cell shape

• Flattened

• Scale- like

Cuboidal epithelial cell shape

• Shaped like squares

• Contain centrally-located nucleus

Columner epithelial cell shape

• Tall, shaped like a column

• Mucus-secreting cells in between cells

Goblet cell

Mucus-secreting cells

Simple squamous epithelial tissue functions

• rapid diffusion

• filtration of substances out of blood

• smooth lining to prevent friction

Locations of simple squamous epithelial tissue

• Walls of alveoli

• lining of heart, blood vessels, and body cavities

Simple cuboidal epithelial tissue functions

• Secretion of glands

• Absorption of water

Locations of simple cuboidal epithelial tissue

• Kidney

• Glands

• Choroid plexuses of brain

Shape of simple squamous epithelial tissue

• Thin

• Scaled

• 1 layer

Shape of simple cuboidal epithelial tissue

• Squared

• 1 layer

Simple columnar epithelial tissue functions

• Absorption

• Secretion

• Movement of materials

Locations of simple columnar epithelial tissue

• Lining of stomach and intestines

  • Lines cavities to increase surface area & maximize absorption

Shape of simple columnar epithelial tissue

• Tall

• 1 layer

Pseudostratified columnar epithelial tissue functions

• Cilia capture debris

• Move debris/ mucus up to keep lungs clear

Locations of pseudostratified columnar epithelial tissue

• Lines respiratory tract

• Nasal cavity

• Trachea

• Bronci (airways)

Shape of pseudostratified columnar epithelial tissue

• 1 layer

• tall

• has cilia

Keratinized stratified squamous epithelial tissue functions

• Protect against abrasion/ injury, bacteria, and chemicals

• Prevents water loss & waterproofs

Nonkaratinized stratified squamous epithelial tissue

• Protects against friction/ abrasion of moist surfaces

• Lacks dead outer layers

Locations of keratinized stratified squamous epithelial tissue

• Epidermis

Shape of stratified squamous epithelial tissue

• thin

• stacked layers

Purpose of keratin

• protect from bacteria

• waterproof

Rapid diffusion of O2 and CO2 in the lungs uses which epithelial tissue

Simple squamous

Reabsorption of substances and secretion of unwanted substances in kidneys uses what epithelium

Simple cuboidal

Most abundant type of tissue in the body

Connective tissue

Functions of connective tissues

• Bind structures

• Support body

• Provide protection and cushioning

• Storage of fat and minerals

• Immune protection

• Transport substances in body

What is ECM

Extracellular material around cells

• contains fibrous proteins and clear gel/ liquid

• contains large proteins with polysaccharides attached

Proteoglycans

Large proteins in ECM with polysaccharides attached

• attract and trap water in ECM

• Forms liquid/ viscous gel

Types of fibers in ECM

• Collagen

• Elastic

• Reticular

Collagen fibers

Most abundant protein in body

• strong

• flexible

• primary structural protein

• formed by fibroblasts

Elastic fibers

• Contain ribber-like protein (Elastin)

• Stretchy

Reticular fibers

Forms sponge-like framework around blood vessels & within organs

• spleen and lymph nodes

Types of fibrous connective tissue

Loose

• Areolar

• Reticular

Dense

• Regular

• Irregular

Fibrous connective tissue

• Good regenerative ability

• Most widely distributed connective tissue

Most diverse type of connective tissue

Fibrous connective tissue

Loose, areolar fibrous connective tissue functions

• Provides cushioning (from arrangement in fibers in thick matrix)

• Provides reservoir of H2O around body tissues- holds same amount as there is blood

• “Packing material” between other tissues

• Wraps blood vessels and nerves

Where is loose, areolar fibrous connective tissue found

In the dermis of skin and in underlying subcutaneous tissue

Loose, reticular fibrous connective tissue

• Framework of lymph nodes, spleen, tonsils, and bone marrow

• Space between fibers filled with blood cells

  • Like a sponge filled with blood

Dense connective tissue

Fibers are most prominent element

• collagen/ elastic fibers

Dense, regular connective tissue

• tightly packed collagen fibers

• run in same direction

• sparse blood supply

• scar tissue common when healing

• flexibility with great resistance in one direction

• tendons and ligaments

• elastic tissue

• help arteries withstand high BP

Dense, irregular connective tissue

• thick collagen fibers arranged irregularly

• little room for cells and ground substance

• resistance and tension in several directions

Locations of dense, irregular connective tissue

• forms protective capsule around kidneys, testes, joints

• makes up fascia around muscles

• Sclera of eye (white part)

• forms tough sheath around bones, nerves, and cartilage

Cartilage

• Avascular

• Poor regeneration

• rebound after being compressed

How does cartilage receive nutrients

diffusion from blood vessels in connective tissue wrapping

What does cartilage contain

• collagen fibers

• chondrocytes

• proteoglycans that hold water

Chondrocytes

Cartilage cells

• located in spaces called lacunae

Perichondrium

Connective tissue wrapping

• around cartilage

Types of cartilage

• Hyaline

• Elastic

• Fibrocartilage

Most abundant type of cartilage

Hyaline cartilage

Hyaline cartilage

• Forms “growth plates” & covers ends of bones and joints

• Lubrication/ friction reduction & cushioning at joints

Lacunae

“Soap dish”

Holds cell in place

Elastic cartilage

• Ears and end of nose

• Maintains structural shape

• Allows bending and deformation

Fibrocartilage

• intervertebral disks, meniscus joints, pubic symphysis

• shock absorption, resists compression, joint stability

Why does cartilage heal slowly

It is avascular, so it lacks blood supply

Osseous tissue

Bone

Bone functions

• Supports and protects body structures

• Site of blood cell formation

• Vascularized and has nerves

• Good regenerative abilities

Why are bones harder than cartilage

• Has calcium and phosphate salts in ECM

Cyte

Cell

Types of bone tissue

• Compact bone

• Trabecular bone

Compact bone tissue

• Solid bone → outside of all bones

• Osteons

• Primary structural framework that supports body weight & resists bending, twisting, and compressive forces

Purpose of compact bone structure

Dense, solid structure

• Withstand stresses of weight-bearing and impact activites

Osteons

Microscopic arrangement into units

• resemble tree trunks with rings

Osteocyte

Bone cells

• maintain bone tissue

Osteoblast

Build bone tissue

Osteoclast

Break down bone tissue

Where to find trabecular bone

Under compact bone

Trabecular bone tissue structure

• “Open spaces” between plates of bone (lamellae)

  • filled with red bone marrow

• Light weight, but still provides support

Lamellae

open spaces between thin plates of bone

Trabecular bone tissue functions

• calcium and phosphate homeostasis

• adapts architecture to match mechanical demands

  • becomes thicker in areas of high stress & vice versa

• shock absorption

Blood tissue

• Fluid ECM called plasma

• Constant regeneration from stem cells in red bone marrow

Cells of blood tissue

• Erythrocytes- most abundant

• Leukocytes

• Thrombocytes

Erythrocytes

Red blood cells

• pick up O2 in lungs and deliver to tissues

• pick up CO2 from tissues and deliver to lungs

Leukocytes

White blood cells

• Several types

• Play important role in immune system

Thrombocytes

Platelets

• Essential for blood clotting

  • fragments, not complete cells

Adipose tissue

• highly vascularized

• good regenerative capacity

• cells shrink/ grow depending on energy demands

Adipose tissue stats

• not much ECM → 90% cells

• 18% of body weight

Types of fat

• Brown fat

• White fat

• Yellow fat

Brown fat

• Non-shivering temp regulation

• Generates heat without muscle contraction

White fat

• Triglyceride storage

  • stores excess calories as triglycerides in large liquid droplets

• Energy mobilization

• Cushioning

• Insulation

• Release hormones

Energy mobilization in fats function

Release free fatty acids during periods of energy demand

Cushioning and protection in fats function

Protects organs from mechanical trauma

Insulation in fats function

Provides thermal insulation in subcutaneus fat

Yellow fat

Fills spaces in trabecular bone that’s not with bone marrow

• Can be converted back to red bone marrow need be

Yellow fat in kids

Originally red fat as a kid, but turns yellow with age