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4 Tissues

PowerPoint® Lecture Presentations prepared by Leslie Hendon University of Alabama, Birmingham © 2014 Pearson Education, Inc.

I. Tissues A. Cells work together in functionally related groups called tissues

B. Tissue - A group of closely associated cells that perform related functions and are similar in structure

II. Four Basic Tissue Types and Basic Functions ► Epithelial tissues - covering ► Connective tissues - support ► Muscle tissues - movement ► Nervous tissue - control

III. Epithelial Tissue A. Covers all body surfaces and lines all body cavities B. Functions of epithelia 1. protection 2. secretion 3. absorption 4. diffusion 5. filtration 6. sensory reception

C. Special Characteristics of Epithelia 1. cellularity - cells separated by minimal extracellular material 2. specialized contacts - cells joined by special junctions 3. polarity - cell regions of the apical surface differ from the basal surface 4. avascular (no blood vessels) - epithelia receive nutrients from underlying connective tissue 5. regeneration - lost cells are quickly replaced by cell division

Cilia

Narrow extracellular space

Microvilli Apical region of an epithelial cell Cell junctions Tight junction Adhesive belt Desmosome Gap junction

Epithelium

Basal region

Nerve ending Connective tissue

Capillary

Basal lamina Reticular fibers

Basement membrane

► First name of tissue indicates number of cell layers Simple epithelia - single layer of cells attached to basement membrane

Stratified epithelia - multiple layers of cells (basal cells attached to basement membrane) ► Last name of tissue describes shape of cells Squamous—cells are wider than tall (plate-like) Cuboidal—cells are as wide as tall, like cubes

Columnar—cells are taller than they are wide, like columns

Apical surface

Basal surface

Simple Apical surface

Basal surface

Stratified

Classification based on number of cell layers

Squamous

Cuboidal

Columnar Classification based on cell shape

Simple Squamous Epithelium Description A. single layer; flat cells with disc-shaped nuclei

Functions A. passage of materials by passive diffusion and filtration B. secretes lubricating substances in serosae

Location A. alveoli of lungs B. renal corpuscles C. lining of heart, blood, and lymphatic vessels D. lining of ventral body cavity (serosae)

Simple squamous epithelium Description: Single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithelia.

Function: Allows passage of materials by diffusion and filtration in sites where protection is not important; produces lubricating fluid in serosae.

Air sacs of lung tissue Nuclei of squamous epithelial cells

Location: Kidney glomeruli; air sacs of lungs; lining of heart, blood vessels, and lymphatic vessels; lining of ventral body cavity (serosae). Photomicrograph: Simple squamous epithelium forming part of the alveolar (air sac) walls (140).

Simple squamous epithelium

Simple Cuboidal Epithelium Description A. single layer of cube-like cells; large, spherical central nuclei

Function A. secretion and absorption Location A. kidney tubules, small glands, ovary surface

Simple cuboidal epithelium Description: Single layer of cubelike cells with large, spherical central nuclei.

Simple cuboidal epithelial cells Function: Secretion and absorption. Basement membrane

Location: Kidney tubules; ducts and secretory portions of small glands; ovary surface.

Connective tissue Photomicrograph: Simple cuboidal epithelium in kidney tubules (430).

Simple Columnar Epithelium Description—single layer of column-shaped (rectangular) cells A. some bear cilia at their apical surface B. may contain goblet cells Function A. absorption; secretion of mucus, enzymes, and other substances B. ciliated type propels mucus or reproductive cells by ciliary action

Location A. nonciliated- stomach, intestines, gall bladder B. ciliated – bronchi, uterine tubes, uterus

Simple columnar epithelium Description: Single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucus-secreting unicellular glands (goblet cells). Microvilli Goblet cell Simple columnar epithelial cell

Function: Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action. Location: Nonciliated type lines most of the digestive tract (stomach to anal canal), gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus.

Basement membrane Photomicrograph: Simple columnar epithelium of the small intestine (650).

Pseudostratified Columnar Epithelium Description A.like simple columnar, but uneven surface B. may contain goblet cells and bear cilia C. nuclei lie at varying heights within cells D. gives false impression of stratification Function—secretion of mucus; propulsion of mucus by cilia

Locations A. non-ciliated type i. ducts of male reproductive tubes ii. ducts of large glands B. ciliated type i. lines trachea and most of upper respiratory tract

Pseudostratified columnar epithelium Description: Single layer of cells of different heights, some not reaching the free surface; nuclei seen at different levels; may contain mucus-secreting goblet cells and bear cilia.

Cilia Goblet cell

Pseudostratified epithelial layer

Function: Secretion, particularly of mucus; propulsion of mucus by ciliary action. Location: Nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract. Trachea

Basement membrane Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (780).

Stratified Squamous Epithelium Description A. many layers of cells are squamous in shape B. deeper layers of cells appear cuboidal or columnar C. thickest epithelial tissue D. adapted for protection from abrasion 1. Keratinized a. Location - epidermis of the skin b. contains the protective protein keratin c. waterproof d. surface cells are dead and full of keratin 2. Non-keratinized a. Forms moist lining of body openings

Stratified squamous epithelium Description: Thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers.

Stratified squamous epithelium

Function: Protects underlying tissues in areas subjected to abrasion.

Nuclei Basement membrane

Location: Nonkeratinized type forms the moist linings of the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane.

Connective tissue Photomicrograph: Stratified squamous epithelium lining the esophagus (280).

Stratified Cuboidal Epithelium (rare) Description - generally two layers of cube-shaped cells Function - protection Location A. Forms ducts of:

1. mammary glands 2. salivary glands 3. largest sweat glands

Stratified cuboidal epithelium Description: Generally two layers of cubelike cells. Basement membrane

Function: Protection.

Location: Largest ducts of sweat glands, mammary glands, and salivary glands.

Cuboidal epithelial cells

Duct lumen

Photomicrograph: Stratified cuboidal epithelium forming a salivary gland duct (290).

Stratified Columnar Epithelium (rare) Description

A. several layers B. basal cells usually cuboidal superficial cells elongated Function - protection and secretion

Location A. rare tissue type B. found in male urethra and large ducts of some glands

Stratified columnar epithelium Description: Several cell layers; basal cells usually cuboidal; superficial cells elongated and columnar.

Stratified columnar epithelium

Function: Protection; secretion.

Location: Rare in the body; small amounts in male urethra and in large ducts of some glands.

Urethra

Basement membrane Underlying connective tissue

Photomicrograph: Stratified columnar epithelium lining the male urethra (360).

Transitional Epithelium Description A. characteristics of stratified cuboidal and stratified squamous B. superficial cells dome-shaped when bladder is relaxed C. squamous when full Function

A. permits distension of urinary organs when filled with urine Location - urinary bladder and ureters

Transitional epithelium Description: Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamous-like, depending on degree of organ stretch.

Transitional epithelium

Function: Stretches readily and permits distension of urinary organ by contained urine. Location: Lines the ureters, bladder, and part of the urethra.

Photomicrograph: Transitional epithelium lining the bladder, relaxed state (365); note the bulbous, or rounded, appearance of the cells at the surface; these cells flatten and become elongated when the bladder is filled with urine.

Basement membrane Connective tissue

V. Glands A. Endocrine glands (INTO the blood)

1. ductless glands 2. secrete directly into surrounding tissue fluid 3. produce messenger molecules called hormones B. Exocrine glands (ONTO a surface) 1. ducts carry substances to epithelial surface a. mucus-secreting glands b. sweat and oil glands c. salivary glands d. liver and pancreas

C. Unicellular Exocrine Glands (The Goblet Cell) 1. goblet cells produce mucin 2. mucin  water  mucus 3. protects and lubricates many internal body surfaces 4. goblet cells are a unicellular exocrine gland (e.g. intestine)

D. Multicellular Exocrine Glands 1. have two basic parts 2. epithelium-walled duct 3. classified by structure of duct a. simple b. compound c. tubular d. alveolar e. tubuloalveolar

Tubular secretory structure

Alveolar secretory structure

Simple duct structure

Compound duct structure

(duct does not branch)

(duct branches)

Simple tubular

Simple branched tubular

Example

Example

Compound tubular

Intestinal glands

Stomach (gastric) glands

Duodenal glands of small intestine

Simple alveolar

Simple branched alveolar

Example No important

Example Sebaceous (oil)

example in humans

glands

Surface epithelium

Duct

Example

Compound alveolar

Example

Mammary glands

Compound tubuloalveolar

Example

Salivary glands Secretory epithelium

E. Cell Junctions 1. factors binding epithelial cells together 2. adhesion proteins link plasma membranes of adjacent cells F. Special cell junctions 1. tight junctions - close off intercellular space a. found at apical region of most epithelial tissues types b. some proteins in plasma membrane of adjacent cells are fused c. prevent molecules from passing between cells

2. adhesive belt junctions - anchoring junction 3. transmembrane linker proteins a. attach to cytoskeleton and bind adjacent cells

4. desmosomes—main junctions for binding cells together a. scattered along abutting sides of adjacent cells b. intermediate filaments extend across the cytoplasm c. and anchor at desmosomes on opposite side of the cell d. are common in cardiac muscle and epithelial tissue 5. gap junctions - passageway between two adjacent cells a. let small molecules move directly between cells b. cells are connected by hollow protein channel c. passage of small atoms (e.g. ions) or molecules d. function in intercellular communication

Plasma membranes of adjacent cells

Microvilli

Intercellular space

Basement membrane

Intercellular space Plaque

Channel between cells (connexon)

Interlocking junctional proteins

Intercellular space

Intercellular space

Intermediate filament (keratin)

Tight junctions: Impermeable junctions prevent molecules from passing through the intercellular space.

Linker glycoproteins (cadherins)

Desmosomes: Anchoring junctions bind adjacent cells together and help form an internal tension-reducing network of fibers.

Gap junctions: Communicating junctions allow ions and small molecules to pass from one cell to the next for intercellular communication.

G. The Basal Lamina 1. at boundary between the epithelium and connective tissue 2. non-cellular supporting sheet between the epithelial tissue 3. connective tissue deep to it 4. consists of proteins secreted by epithelial cells 5. Functions

a. determining which molecules from capillaries enter the epithelium b. scaffolding along which regenerating epithelial tissue cells can migrate c. underlying connective tissue deep to it form the basement membrane

VI. Epithelial Surface Features A. Microvilli—fingerlike extensions of plasma membrane

1. have a core of actin filaments that stiffen the microvillus 2. abundant in kidney tubules and small intestine 3. surface across which small molecules enter or leave cells

Microvilli

Microvillus

Actin filaments

B. Cilia – whiplike extensions of apical surface membranes 1. microtubules held together by cross-linking proteins 2. microtubules arranged in pairs called doublets 3. movement is generated when adjacent doublets grip each other with the motor protein dynein 4. cilia originate as microtubules assemble around centrioles

Cilia Layer of mucus

Cell surface

VII. Connective Tissue A. Most diverse and abundant tissue

B. Main classes of connective tissue 1. connective tissue proper 2. cartilage 3. bone tissue 4. blood

C. Important functions of connective tissue type 1. form basis of the skeleton 2. store and carry nutrients 3.surround blood vessels and nerves 4. support and binding of other tissues 5. holding body fluids (interstitial fluid  lymph) 6. defending body against infection 7. storing nutrients as fat and protection

D. Special Characteristics of Connective Tissue 1. few cells, abundant extracellular matrix 2. extracellular matrix is composed of ground substance 3. extracellular fibers 4. extracellular matrix produced by cells called fibroblasts 5. common embryonic origin is mesenchyme

E. Structural Elements of Connective Tissue 1. connective tissues differ in structural properties 2. differences in types of cells 3. differences in composition of extracellular matrix 4. however, connective tissues all share structural elements

F. Cells 1. fibroblasts - primary cell type of connective tissues produces the extracellular matrix

2. chondroblasts secrete matrix in cartilage (chondro) 3. osteoblasts secrete matrix in bone (osteo)

G. Fibers 1. Extracellular matrix is composed of fibers and ground substance 2. Fibers function in support and also have unique properties a. collagen fibers - strongest; resist tension b. reticular fibers - bundles of special type of cartilage c. elastic fibers - contain elastin

H. Ground substance 1. Is produced by primary cell type of the tissue

2. Is usually gel-like substance consisting of: a. proteoglycans and glycosaminoglycans (arthritis) b. cushions and protects body structures c. holds tissue fluid

Connective Tissue

Extracellular matrix Ground substance

Macrophage

Fibers Collagen fiber Elastic fiber Reticular fiber

Fibroblast Lymphocyte

Fat cell Mast cell

Neutrophil

Capillary

VIII. Embryonic Connective Tissue (Mesenchyme) A. has gel-like ground substance B. cells are star-shaped mesenchymal cells C. connective tissues arise from mesenchyme in the embryo

Embryonic connective tissue: mesenchyme Description: Embryonic connective tissue; gel-like ground substance containing fibers; star-shaped mesenchymal cells. Mesenchymal cells Ground substance Function: Gives rise to all other connective tissue types.

Fibers

Location: Primarily in embryo.

Photomicrograph: Mesenchyme, an embryonic connective tissue (385). The matrix is composed of the fluid ground substance (clear-appearing background) and fine, sparse fibers.

IX. Areolar (Loose) Connective Tissue A. underlies all epithelial tissues B. between muscle and skin C. surrounds small nerves and blood vessels D. structures & functions shared by other connective tissues E. fibers provide support F. Three types of protein fibers in extracellular matrix a. collagen fibers b. reticular fibers c. elastic fibers ► Fibroblasts produce these fibers

G. Tissue fluid (interstitial fluid) 1. watery fluid in extracellular matrix (comes from blood plasma) K. Ground substance 1. made and secreted by fibroblasts 2. viscous, spongy part of extracellular matrix a. Consists of sugar and protein molecules

Main battlefield in fight against infection i. macrophages ii. plasma cells iii. mast cells iv. white blood cells v. neutrophils

Description 1. gel-like matrix with all three fiber types 2. cells of areolar connective tissue 3. fibroblasts, macrophages, mast cells, white blood cells Function 1. wraps and cushions organs 2. holds and conveys tissue fluid (interstitial fluid) 3. Important role in inflammation Locations

1. widely distributed under epithelia 2. ackages organs 3. surrounds capillaries

Connective tissue proper: loose connective tissue, areolar Description: Gel-like matrix with all three fiber types; cells: fibroblasts, macrophages, mast cells, and some white blood cells.

Elastic fibers

Ground substance Function: Wraps and cushions organs; its macrophages phagocytize bacteria; plays important role in inflammation; holds and conveys tissue fluid.

Fibroblast nuclei

Collagen fibers

Location: Widely distributed under epithelia of body, e.g., forms lamina propria of mucous membranes; packages organs; surrounds capillaries. Photomicrograph: Areolar connective tissue, a soft packaging tissue of the body (340). Epithelium Lamina propria

X. Adipose Tissue Description 1. closely packed adipocytes 2. have nucleus pushed to one side by fat droplet 3. highly vascularized Function 1. provides reserve food fuel 2. insulates against heat loss 3. supports and protects organs Location

1. under skin (hypodermis) 2. around kidneys 3. behind eyeballs, within abdomen, and in breasts

Connective tissue proper: loose connective tissue, adipose Description: Matrix as in areolar connective tissue, but very sparse; closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet.

Nucleus of fat cell

Function: Provides reserve food fuel; insulates against heat loss; supports and protects organs.

Vacuole containing fat droplet

Location: Under skin in the hypodermis; around kidneys and eyeballs; within abdomen; in breasts. Adipose tissue Photomicrograph: Adipose tissue from the subcutaneous layer under the skin (350). Mammary glands

XI. Reticular Connective Tissue Description - network of reticular fibers in loose ground substance Function

1. forms a soft, internal skeleton (stroma) 2. supports other cell types Location - Lymph nodes, bone marrow, and spleen

Connective tissue proper: loose connective tissue, reticular Description: Network of reticular fibers in a typical loose ground substance; reticular cells lie on the network.

White blood cell (lymphocyte)

Function: Fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages.

Reticular fibers

Location: Lymphoid organs (lymph nodes, bone marrow, and spleen).

Spleen

Photomicrograph: Dark-staining network of reticular connective tissue fibers forming the internal skeleton of the spleen (350).

XII. Dense Connective Tissue A. Two types of dense connective tissue 1. Dense irregular connective tissue 2. Dense regular connective tissue (have more collagen than areolar connective tissue)

B. Dense Irregular Connective Tissue Description

1. collagen fibers are thick and irregularly arranged 2. contains some elastic fibers and fibroblasts Function

1. withstands tension 2. provides structural strength Location

1. dermis of skin 2. submucosa of digestive tract 3. fibrous capsules of joints 4. capsules surrounding organs (e.g. kidneys, bones, and lymph nodes )

Connective tissue proper: dense connective tissue, dense irregular Description: Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast; defense cells and fat cells are also present. Nuclei of fibroblasts

Function: Able to withstand tension exerted in many directions; provides structural strength.

Collagen fibers

Location: Fibrous capsules of organs and of joints; dermis of the skin; submucosa of digestive tract. Fibrous layer of joint capsule

Photomicrograph: Dense irregular connective tissue from the dermis of the skin (300).

C. Dense Regular Connective Tissue Description a. collagen fibers are parallel to the direction of pull b. fibroblasts are located between collagen fibers c. contains few elastic fibers d. has great tensile strength e. poorly vascularized f. forms fascia (tissue around muscles and tedons)

Function a. attaches muscle to bone b. attaches bone to bone c. withstands great stress in one direction

Location a. tendons and ligaments b. aponeuroses (broad sheet-like tendons) c. fascia around muscles

Connective tissue proper: dense connective tissue, dense regular Description: Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast. Collagen fibers

Function: Attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction.

Nuclei of fibroblasts

Location: Tendons, most ligaments, aponeuroses.

Shoulder joint Ligament Tendon

Photomicrograph: Dense regular connective tissue from a tendon (425).

D. Elastic Connective Tissue Description - Elastic fibers predominate Function - allows recoil after stretching

Location a. within walls of arteries b. in certain ligaments c. surrounding bronchial tubes

Connective tissue proper: dense connective tissue, elastic

Description: Dense regular connective tissue containing a high proportion of elastic fibers.

Function: Allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration.

Elastic fibers

Location: Walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes.

Aorta Heart

Photomicrograph: Elastic connective tissue in the wall of the aorta (250).

Photomicrograph: Elastic connective tissue in the wall of the aorta (250).

XIII. Cartilage A. all cartilages have similar structural components 1. firm, flexible tissue 2. contains no blood vessels or nerves 3. matrix contains up to 80% water 4. chondrocytes – mature cells 5. chondroblasts - immature cells for growth and maintenance a. secrete matrix of fibers during cartilage growth

B. Three types of cartilage 1. Hyaline cartilage 2. Elastic cartilage 3. Fibrocartilage

► Each cartilage has specialized functions

C. Hyaline Cartilage Description a. imperceptible collagen fibers (hyaline = glassy) b. are mature cartilage cells c. lie within lacunae Function a. supports and reinforces b. resilient cushion c. resists repetitive stress Location a. fetal skeleton b. ends of long bones c. costal cartilage of ribs d. cartilages of nose, trachea, and larynx

Cartilage: hyaline

Description: Amorphous but firm matrix; collagen fibers form an imperceptible network; chondroblasts produce the matrix and, when mature (chondrocytes), lie in lacunae.

Chondrocyte in lacuna

Matrix

Function: Supports and reinforces; serves as resilient cushion; resists compressive stress. Location: Forms most of the embryonic skeleton; covers the ends of long bones in joint cavities; forms costal cartilages of the ribs; cartilages of the nose, trachea, and larynx. Costal cartilages

Photomicrograph: Hyaline cartilage from a costal cartilage of a rib (470).

D. Elastic Cartilage Description a. similar to hyaline cartilage b. more elastic fibers in matrix

Function a. maintains shape of structure b. allows great flexibility Location a. supports external ear b. epiglottis

Cartilage: elastic Description: Similar to hyaline cartilage, but more elastic fibers in matrix.

Chondrocyte in lacuna

Function: Maintains the shape of a structure while allowing great flexibility.

Matrix

Location: Supports the external ear (pinna); epiglottis. Photomicrograph: Elastic cartilage from the human ear pinna; forms the flexible skeleton of the ear (510).

E. Fibrocartilage Description a. matrix similar but less firm than hyaline cartilage b. thick collagen fibers predominate Function - tensile strength and ability to absorb compressive shock Location a.intervertebral discs b. pubic symphysis c.discs of knee joint

Cartilage: fibrocartilage Description: Matrix similar to but less firm than that in hyaline cartilage; thick collagen fibers predominate.

Function: Tensile strength with the ability to absorb compressive shock.

Collagen fibers

Location: Intervertebral discs; pubic symphysis; discs of knee joint.

Chondrocytes in lacunae

Intervertebral discs Photomicrograph: Fibrocartilage from an intervertebral disc (175).

XIV. Bone Tissue Description bone matrix contains: 1. inorganic Calcium salts 2. abundance of collagen fibers 3. well vascularized ► osteoblasts—secrete collagen fibers; create/maintain/remodel bone ► osteocytes—mature bone cells in lacunae ► (osteoclasts) – degrade bone during remodeling and repair

Function 1. supports and protects organs 2. provides levers and attachment site for muscles 3. stores calcium and other minerals 4. stores fat 5. bone marrow - site for blood cell formation Location - Bones

Others: bone (osseous tissue) Description: Hard, calcified matrix containing many collagen fibers; osteocytes lie in lacunae. Very well vascularized. Central canal Lacunae

Function: Supports and protects (by enclosing); provides levers for the muscles to act on; stores calcium and other minerals and fat; marrow inside bones is the site for blood cell formation (hematopoiesis).

Lamella

Location: Bones.

Photomicrograph: Cross-sectional view of bone (175).

XV. Blood Tissue Properties 1. an atypical connective tissue 2. develops from mesenchyme (embryonic tissue) 3. consists of cells surrounded by nonliving matrix Description 1. Red blood cells, white blood cells and platelets

Function - Transport of respiratory gases, nutrients, and wastes Location – within blood vessels and heart

Connective tissue: blood Description: Red and white blood cells in a fluid matrix (plasma). Red blood cells (erythrocytes) White blood cells: • Lymphocyte • Neutrophil Function: Transport respiratory gases, nutrients, wastes, and other substances.

Location: Contained within blood vessels.

Plasma

Photomicrograph: Smear of human blood (1650); shows two white blood cells surrounded by red blood cells.

XVI. Covering and Lining Membranes A. combine epithelial tissues and connective tissues B. cover broad areas within body C. epithelial sheet plus underlying connective tissue

D. Three Types of Membranes 1. cutaneous membrane 2. mucous membranes 3. serous membranes

1. Cutaneous membrane

a. skin 2. Mucous membranes a. lines hollow organs that open to surface of body

b. epithelial sheet with layer of lamina propria

3. Serous membranes a. simple squamous epithelium called mesothelium b. produces serous fluid c. lines closed cavities

i. visceral and parietal pleura (lungs) ii. visceral and parietal peritoneum (intestines) iii. visceral and parietal pericardium (heart)

Cutaneous membrane The cutaneous membrane (the skin) covers the body surface.

Serous membranes Serous membranes line body cavities that are closed to the exterior.

Cutaneous membrane (skin) Parietal pleura Visceral pleura Mucous membranes

Visceral Parietal pericardium pericardium

Mucous membranes line body cavities that are open to the exterior. Mucosa of nasal cavity

Mucosa of mouth Esophagus lining Mucosa of lung bronchi

Parietal peritoneum Visceral peritoneum

XVII. Muscle Tissue A. is a composite tissue B. contains areolar connective tissue and muscle tissue C. muscle cells also called muscle fibers

D. cells contain myofilaments 1. myofilaments contain actin and myosin E. Three types of muscle tissue

1. skeletal muscle tissue 2. cardiac muscle tissue 3. smooth muscle tissue

F. Skeletal Muscle Tissue (Striated muscle; Voluntary muscle)

Description 1. long, cylindrical cells 2. multinucleate 3. obvious striations Function - voluntary movement Location - skeletal muscles attached to bones (occasionally to skin)

Skeletal muscle Description: Long, cylindrical, multinucleate cells; obvious striations. Striations

Nuclei

Function: Voluntary movement; locomotion; manipulation of the environment; facial expression.

Location: In skeletal muscles attached to bones or occasionally to skin.

Part of muscle fiber (cell)

Photomicrograph: Skeletal muscle (450). Notice the obvious banding pattern and the fact that these large cells are multinucleate.

G. Cardiac Muscle Tissue Description 1. branching cells, striated 2. generally uninucleate 3. cells interdigitate at intercalated discs Function - contracts to propel blood into circulatory system Location - occurs in walls of heart

Cardiac muscle

Description: Branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs). Striations Intercalated discs

Function: As it contracts, it propels blood into the circulation; involuntary control. Location: The walls of the heart.

Nucleus

Photomicrograph: Cardiac muscle (355); notice the striations, branching of cells, and the intercalated discs.

Cardiac muscle

H. Smooth Muscle Tissue

Description 1. spindle-shaped cells with central nuclei 2. arranged closely to form sheets 3. no striations Function 1. propels substances along internal passageways 2. involuntary control Location - walls of blood vessels and GI tract

Smooth muscle Description: Spindle-shaped cells with central nuclei; no striations; cells arranged closely to form sheets. Smooth muscle cell Function: Propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control.

Nuclei

Location: Mostly in the walls of hollow organs.

Photomicrograph: Sheet of smooth muscle from the digestive tract (465).

XVIII. Nervous Tissue Description 1. main components are brain, spinal cord, and nerves 2. contains two types of cells:

a. neurons (nerve cells)- conduct nerve impulses b. neuroglial cells (supporting cells) - supporting cells Function - transmit electrical signals

Location - brain, spinal cord, and nerves

Nervous tissue Description: Neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonconducting supporting cells, neuroglia (not illustrated). Neuron processes

Cell body of a neuron

Neuron processes

Cell body

Dendrites Axon Function: Transmit electrical signals from sensory receptors and to effectors (muscles and glands) that control the activity of the effector organs. Location: Brain, spinal cord, and nerves.

Nuclei of neuroglia

Photomicrograph: Neurons (125).