Biol 260 - Exam 2 - Muscles and Tissues

Connective tissue consists of what two basic elements: 

Cells 

Extracellular matrix 

Characteristics of Cells and Tissues

Cells: do not have any free surfaces

• immature cells have names that end in -blast 

• mature cells have names that end in -cyte

Tissue: highly vascularized and has a nerve supply 

• except tendons and cartilage 

What do these connective tissues do: 

Mature

Fibrous 

Supporting 

Liquid 

Mature: connective tissue present at birth and persists through life 

Fibrous: flexible and contains viscous ground substance and many fibers 

Supporting: protects and supports soft tissues of the body 

Liquid: extracellular matrix is liquid

Examples of mature CT?

Bone

Dense irregular

Hyaline

What makes up the supportive ct?

• Chondroblasts and chondrocytes

• Osteoblasts and osteocytes 

What makes up the liquid ct?

Formed elements: cellular components of blood

• Erythrocytes

• Leukocytes

• Platelets (thrombocytes) 

Ground substance

Aka ECF = fluid/gel component of EM

• contains water, gases, nutrients, minerals, wastes, hormones, and other chemicals 

The three classes of large molecules that make up the ground substance 

• Glycosaminoglycan (GAG)

• Proteoglycans

• Adhesive glycoproteins 

Glucosaminoglycan (GAG)

Long polysaccharide w/ unusual composition

• Negatively charged, attracts sodium and potassium ions, making GAG absorb and retain water

• Regulate water and electrolyte balance

Proteoglycans

Giant molecule shaped like a bottle brush w/ central core protein and bristles of GAGs

• Attach to hyaluronic acid to make enormous complex

• Slows spread of pathogens and helps hold tissues together 

• Form thick colloids like gravy, gelatin, or glue

Adhesive glycoproteins

Protein/carbohydrate complexes

• Bind plasma membrane proteins to extracellular collagen and proteoglycans

• Bind components of tissue together

• Mark paths to guide migrating embryonic cells to their destination tissue

Characteristics of Epithelial tissue

• Closely packed cells with little extracellular material 

• Cells sit on basement membrane 

• Avascular 

• Good nerve supply

• Rapid cell division

Function of the basement membrane is to

• Anchor cells 

• Guide for cell migration during development 

• Restricts passage between epithelial and connective tissues 

Urothelium aka transitional epithelium

Appearance:

• Somewhat resembles stratified squamous
  epithelium but w/ rounded surface cells that
  bulge at the surface

• Typically 5-6 cells thick when relaxed, only 2-3 cell
  layers thick when stretched

• Some cells have two nuclei

Locations:

• Urinary tract – kidney, bladder, ureter, urethra

Functions

• stretching to allow filling of urinary tract

• protects underlying tissues from damage by urine

4 major types of tissues

• Epithelial

• Connective

• Muscular

• Nervous

Simple vs Stratified

Simple: one layer

Stratified: multiple layers of cells

Label the apical vs basal surface in both simple and stratified epithelia

Classification of epithelia are?

Squamous, cuboidal, or columnar

Simple Squamous Epithelial

Function: filtration (kidneys) and rapid diffusion (air sacs of lungs)

Location: kidney glomeruli, alveoli of lungs, lining of heart, kidney corpuscles, and blood and lymphatic vessels

Keratinized Stratified Squamous Epithelia

Function: protects underlying tissue in areas subject to abrasion and penetration, retards water loss through skin

Location: epidermis, palms and soles (heavily keratinized)

For stratified epithelia, why do we name based off cells on apical surface?

All cells connected to basal membrane will either be cuboidal or columnar

Simple Cuboidal

Description: Single layer of cubelike cells with large, spherical central nuclei

Function: Secretion and absorption, production of mucous coat, movement of respiratory mucus

Location: Kidney tubules, ducts and secretory portions of small glands, and liver

Simple Columnar

Description: Single layer of tall, column-like cells with oval nuclei

Function: Protection, secretion of mucus, absorption

Location: Lining of stomach, intestine, gallbladder, uterine tube, collecting ducts of kidneys

Label the simple columnar

• free surface

• goblet cell containing mucus

• nucleus

• basement membrane

Ciliated Pseudostratified Columnar

Function: Secretion and propulsion of mucus

Location: Lining of ducts, ciliated: lines trachea and most of upper respiratory tract

Characteristics:

• Has goblet cells that secret mucus & is ciliated

• Looks layered, but only has a single layer of cells

Transitional

Description: Multiple layers of cells that can change shape depending on the degree of stretching.

Function: Stretches readily and permits distension of urinary organ by contained urine

Location: Lines the ureters, bladder, and part of the urethra

Connective tissue

Found throughout the body; most abundant and widely distributed of all the tissues

• Four main types:

  • connective tissue proper

  • cartilage

  • bone

  • blood

Characteristics: Tissues with large matrix inside of it, rich supply of blood vessels, composed of many types of cells

Loose Areolar CT

Appearance: loose arrangement of collagenous and elastic fibers

CT Type: CT proper

Fibers: Collagen, elastic

Function: Wraps and cushions all internal organs - attached to all epithelial tissue (connects skin to deep tissues)

Location: in serous membranes, between muscles, passageways for nerves and blood. underlies all epithelia

Label the Areolar CT

Dense Regular Tissue

CT Type: CT Proper

Fibers: Collagen fibers tightly packed together

Function: Withstand force in one direction - resist stress

Location: In tendons and some ligaments

Characteristics: Parallel collagen fibers in one direction and compressed fibroblast nuclei

Label the Dense Regular CT

Tendons do what? Ligaments do what?

Tendons attach muscles to bones and ligaments hold bones together

Adipose CT

CT Type: CT Proper

Function: Insulation, cushions and protects organs, and reserve fuel

Location: Under skin in the abdomen, around kidneys & eyeballs, in breasts

Characteristics: Nucleus pressed against cell membrane

Label the Adipose CT

Reticular CT

CT Type: CT Proper

Function: Provides a framework for white blood cells, mast cells, and macrophages - all a part of the immune system

Location: Lymphoid organs: spleen, lymph nodes, and bone marrow

Characteristics: Mesh of reticular fibers and fibroblasts

Label the Reticular CT

Bone (osseous tissue) CT

Function: Structural support, give body its shape, act as attachment points for muscles

Location: Bones

Characteristics: Arranged in cylinders that surround central (haversian or osteonic) canals that run longitudinally through shafts of long bones

Label the Compact Bone

Haversian Canal

A series of tubes around narrow channels formed by lamellae

Hyaline Cartilage

Function: Supports and reinforces structures (like bone), but can bend - eases joint movement

Location: Ends of long bones, connects ribs to sternum, found at end of nose, in trachea and larynx

Characteristics: Pairs of lacunae, clear, glassy microscopic appearance. Covered by perichondrium

Label the Hyaline Cartilage

Blood CT

Function: transport respiratory gases and dissolve matter from place to place

Location: in blood vessels

Characteristics: Formed in the bone marrow and fluid connective tissue

Plasma

Blood’s liquid ground substance

Formed elements

Cells and cell fragments

Erythrocytes

Red blood cells: transport O2 and CO2

Leukocytes

White blood cells: defense against infection and other diseases

Thrombocytes

Cell fragments involved in clotting and other mechanisms

Label the blood CT

Smooth Muscle tissue

Function: involuntary control - propels substances along redetermined pathways

Location: digestive, respiratory, and urinary tract - visceral muscles

Characteristics: lines hollow structures, smooth and no striations

• relatively short, fusiform cells

• One centrally located nucleus

Label the Smooth Muscle

Cardiac Muscle

Function: Propels blood into circulation as it contract

Location: only in the heart

Characteristics:

• involuntary control

• one nucleus surrounded by light-staining glycogen

• shorter, branched, and blunted at ends

• intercalated discs allow the cardiac muscle to act as a unit

• striated

Label the Cardiac Muscle

2 main cell types

Neuroglia: functionally support, protect and insulate neurons and bind them together

Neurons: respond to stimuli and conduct impulses to and from all body organs

Nervous tissue

Function: specialized for communication by electrical and chemical signals

Label the Nervous tissue

Skeletal Muscle

Functions: voluntary control

Location: in skeletal muscles attached to bones or occasionally to skin

Characteristics:

Cells are long

multi-nucleated

striated

threadlike cells

contains multiple nuclei

Label the skeletal muscle

Dense irregular CT

Function: provides strength and elasticity to the skin and underlying structures - withstands unpredictable stresses

Location: found in the dermis of the skin, joint capsules, and organ capsules - fibrous sheaths

Characteristics:

• densely packed

• randomly arranged

• collagen fibers

• few visible cells

Label the Dense Irregular CT

Elastic Cartilage CT

Function: provides flexible, elastic support

Location: external ear and epiglottis

Characteristics:

• covered with perichondrium

Label the Elastic Cartilage

Fibrocartilage CT

Function: resists compression and absorbs shock

Location: pubic symphysis, menisci, and intervertebral discs

Characteristics:

• cartilage containing large, coarse bundles of collagen fibers

• never has perichondrium

Label the fibrocartilage

2 main layers of the skin

Epidermis: stratified into 4 structural layers (or 5 layers in palms and soles)

Dermis: consists of 2 layers

Two types of sweat glands

Eccrine

Apocrine

Eccrine Sweat Glands

• simple, coiled tubular glands

• more common than apocrine

• regulate body temperature through perspiration/evaporation

Apocrine sweat glands

Found: skin of axilla, groin, anal regions, areolae areas of the breasts, and bearded areas of men

• Secretions are more viscous (thicker) than eccrine secretions

Epithelial

Tissue composed of layers of closely spaced cells

Function:

• Protection

• Secretion

• Excretion

• Absorption

• Filtration

• Sensation

Locations:

• Epidermis

• Inner lining of digestive tract

• Liver and other glands

Connective Tissue

Tissue with usually more matrix than cell volume, often specialized to support and protect organs and to bind other tissues and organs to each other

Locations:

• Tendons

• Ligaments

• Cartilage

• Bone

• Blood

Nervous Tissue

Tissue containing excitable cells specialized for rapid intermission of coded information to other cells

Locations:

• Brain

• Spinal cord

• Nerves

Muscular Tissue

Tissue composed of elongated, excitable muscle cells specialized for contraction

Locations:

• Skeletal muscles

• Heart

• Walls of viscera

What’s the difference between longitudinal, cross section and oblique?

Longitudinal sections are sliced along the length of the structure

Cross sections are cut horizontally across it

Oblique sections are cut at an angle, allowing visualization of different cellular features.

Stratified Squamous Epithelium - nonkeratinized

Appearance: Same as keratinized but without the surface of dead cells

Function: Resists abrasion and penetration by pathogenic organisms

Locations: Tongue, oral mucosa, esophagus, anal canal, vagina

The cells of fibrous CT include?

Fibroblasts

Macrophages

Leukocytes

Plasma cells

Mast cells

Adipocytes

Three types of protein fibers characteristics?

Collagenous fibers:

• made of collagen

• tough and flexible

• resist stretching

• most abundant protein

• glistening white fibers

• makes up tendons, ligaments, and the dermis of the skin

Reticular fibers:

• thin collagen fibers

• coated with glycoprotein

• form a spongelike framework for spleen and lymph nodes

Elastic fibers:

• thinner than collagen fibers

• branch and rejoin each other

• made of elastin

• coasted with glycoprotein

• stretch and recoil

Characteristics of muscle 

• Excitability = respond to stimuli with electrical changes across the plasma membrane

• Conductivity = electrical signal travels rapidly along the cell

• Contractility = cell shortens when stimulated

• Extensibility = able to stretch beyond normal resting length without damage

• Elasticity = shortening of a muscle after it is stretched and released; ability of muscle to return to shape after stretching or contracting

Fascia

Fibrous tissue covering of bones and muscles

• holds muscles w/ similar functions together

Epimysium

Outer layer covering muscle; made of dense irregular connective tissue 

Perimysium

Surrounds groups of 10-100 muscle fibers creating bundles called “muscle fascicles”

• made of dense irregular ct 

Endomysium

Penetrates interior of each fascicle and separates fibers from one another 

• mostly reticular fibers 

What forms a tendon?

Three layers of fascia which extend beyond muscle fibers and intertwine with the collagen

Aponeurosis

When layers fuse in a broad sheet