Tissues BIO168 (1)

Bio 168 Lab: 

Bio 168 Lab Tissues and Membranes

Overview …: 

Overview … A tissue is a group of cells with similar structure and function Contributes to the functioning of the organs Membranes are sheets of tissues Each has a specific location and function

Embryonic vs Adult Tissues: 

Embryonic vs Adult Tissues Embryonic Tissues Consider the following embryonic tissues: Endoderm Ectoderm Mesoderm These tissues (often in combinations) give rise to the 4 adult tissues Four Adult Tissues Epithelial tissue Connective tissue Muscle tissue Nervous tissue

A Comment on Locations and Functions : 

A Comment on Locations and Functions This exercise does not list all possible locations and functions for each tissue. This exercise emphasizes locations and functions that will enhance your understanding of the each tissues purpose.

Epithelial Tissue: 

Epithelial Tissue Forms coverings and linings Avascular- it must receive nutrients and oxygen from the connective tissue located beneath it Performs many functions such as secretion, absorption, diffusion, protection, etc. Forms the secretory portion of glands

Characteristics of Epithelial Tissue: 

Characteristics of Epithelial Tissue The next series of slides illustrate the basic characteristics of epithelial tissue

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Apical surface – no tissue attached to this surface Basal surface – faces the basement membrane Basement membrane – acellular region that holds the epithelial tissue to the connective tissue Connective tissue Epithelial tissue

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Apical (free) surface Lateral surfaces Epithelium Basal lamina Reticular lamina Connective tissue Basement membrane Basal surface Click to reveal leader lines Identify the indicated items Click again to reveal answers

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Epithelial cells are tightly packed together with little to no space between cells.

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Adhesion belt Basement membrane Many cell junctions hold adjacent cells together Review as needed

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Epithelial cells form a sheet or sheets

Epithelial tissue is avascular. The blood vessels serving the epithelial tissue are located in the adjacent connective tissue. : 

Epithelial tissue is avascular. The blood vessels serving the epithelial tissue are located in the adjacent connective tissue. Cross section of blood vessel

Classification : 

Classification Based primarily on the shape and number of cell layers 3 Distinct Shapes Squamous= flat Cuboidal= cube Columnar= column Number of layers Simple= single layer Stratified= more than one layer Pseudostratified= falsely layered

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Shapes of Epithelial Tissue

Simple Squamous Epithelium: 

Simple Squamous Epithelium Single layer of flat cells that are very thin and smooth (they look like puzzle pieces). Locations alveoli (air sacs) of the lungs capillary walls Function excellent tissue for diffusion Surface view

Stratified Squamous Epithelium: 

Stratified Squamous Epithelium Has many layers of mostly flat cells (see superficial layers) Deeper cells do not reflect the squamous shape Superficial layers of dry surfaces are keratinized Moist surfaces have non-keratinized cells (oral cavity, esophagus, and vagina). Stratified squamous resists abrasion

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Sectional view of keratinized stratified squamous epithelium of epidermis 400x LM Keratinized (dead) surface cells 100x LM Nucleus of living cell Keratinized stratified squamous epithelium Connective tissue Cells are flat

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Sectional view of nonkeratinized stratified squamous epithelium of lining of vagina 400x LM Nonkeratinized surface cell 630x LM Nonkeratinized stratified squamous epithelium Connective tissue Vagina Cells are flat Cells of the deeper layers are not flat

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Again , surface cells are living and contribute to the mucous membrane. Forms a barrier against microbes due to the cells being so close together Vagina

Simple Cuboidal Epithelium: 

Simple Cuboidal Epithelium A single layer of cubed cells This tissue makes up the secretory portion of glands (thyroid, salivary, etc. ) Thus, their function is secretion Also located in the tubules of kidneys A ciliated version can be found in portions of the resp. tract (sweeps mucus)

PowerPoint Presentation: 

Kidney Sectional view of simple cuboidal epithelium of urinary tubules Connective tissue Simple cuboidal cell Lumen of tubule 100x LM 500x LM Connective tissue

Stratified Cuboidal: 

Stratified Cuboidal More than one layer of cube shaped cells. It is also found lining the ducts of glands and is excellent at secretion.

PowerPoint Presentation: 

Sectional view of stratified cuboidal epithelium of the duct of an esophageal gland 380x LM 640x LM Lumen of duct Lumen of duct Stratified cuboidal epithelium Esophagus Connective tissue

Simple Columnar Epithelium: 

Simple Columnar Epithelium These cells are taller than they are wide (hint: nuclei appear elongated) A nonciliated version (with microvilli): specialized for secretion and absorption found in the linings of the stomach and small intestines A ciliated version: lines portions of the respiratory tract and the fallopian tubes Both types include unicellular glands called goblet cells, which produce mucus Columnar epithelium

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Microvilli (increases surface area) Mucus in goblet cell Basement membrane Connective tissue Nonciliated simple columnar epithelium Nonciliated simple columnar epithelium

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Sectional view of nonciliated simple columnar epithelium of lining of jejunum of small intestine Nonciliated simple columnar epithelium 500x LM Mucus in goblet cell Microvilli Lumen of jejunum Nucleus of absorptive cell Small intestine Basement membrane Connective tissue 1500x LM

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Additional View of Nonciliated Simple Columnar

Ciliated Columnar Epithelium: 

Ciliated Columnar Epithelium Ciliated columnar cells have cilia on their free (apical) surfaces Lines bronchioles Cilia sweep mucus Lines fallopian (uterine) tubes Cilia sweep the egg towards uterus A= Columnar cell B= Cilia C= Nuclei of columnar cells

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500x LM 630x LM Nucleus (appear elongated) Ciliated simple columnar epithelium Connective tissue Cilia Lumen of uterine tube Uterine tube Sectional view of ciliated simple columnar epithelium of uterine tube

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Additional Views of Columnar Epithelium

Pseudostratified Ciliated Columnar: 

Pseudostratified Ciliated Columnar Pseudostratified= falsely layered It is only one cell layer thick, but looks like more than one layer It is an optical trick created by: tapering cells alternating positions of the nuclei The eye wants to create two layers Tapering cells Alternating positions

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Pseudostratified columnar epithelium can be found lining the: Trachea Primary bronchi Secondary bronchi Tertiary bronchi This tissue is designed to sweep mucus

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Mucus in goblet cell Sectional view of pseudostratified columnar epithelium of trachea 400x LM 630x LM Cilia Trachea Connective tissue Cilia Pseudostratified ciliated columnar epithelium 630x LM

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Apical surface Basement membrane Connective tissue Stratified columnar epithelium A stratified version of columnar epithelium also exists, but it is rare. Stratified columnar can be found lining some large glands, and portions of the urethra. Stratified Columnar

Transitional Epithelium: 

Transitional Epithelium A type of stratified epithelium where the surface cells change from round to squamous The urinary bladder is able to fill and stretch without tearing the lining Note: most tissues have some ability to stretch Urinary Bladder

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Sectional view of transitional epithelium of urinary bladder in relaxed (empty) state 400x LM 630x LM Urinary bladder Transitional epithelium Connective tissue Rounded surface cell in relaxed state Nucleus of transitional cell Lumen of urinary bladder

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Sectional view of transitional epithelium of urinary bladder in filled state Lumen of urinary bladder 630x LM 1000x LM Flattened surface cell in filled state Transitional epithelium Connective tissue Lumen of urinary bladder

GLANDS: 

GLANDS Glands are cells that secrete a substance Unicellular Glands Example: goblet cells which secretes mucus Multicellular Glands Either made of many similar cells or a variety of cells with products mingled into a collective secretion There are 2 major groups Exocrine glands Endocrine glands

Exocrine vs. Endocrine Glands: 

Exocrine vs. Endocrine Glands Endocrine Glands Typically lack ducts Secrete hormones Examples of glands: Thyroid gland Pituitary gland Adrenal gland Exocrine glands Typically utilize ducts Secrete to an epithelial surface Surface of the skin Lining of an organ Examples of secretions: Sweat Oil Wax Milk Digestive juices Note: some organs, such as the pancreas, have both endocrine and exocrine functions.

Connective Tissues: 

Connective Tissues Connective tissues are composed of relatively few cells scattered in an acellular matrix The matrix may be fibrous, gel, solid, or liquid

Loose Connective Tissues: 

Loose Connective Tissues Loose connective tissues include: Areolar Adipose Reticular

Areolar Connective Tissue: 

Areolar Connective Tissue Very widely distributed Classic locations include: Beneath all epithelial tissues Dermis of the skin Subcutaneous layer The fibroblasts produce all three fiber types Reticular fibers Collagen fibers (strong) Elastic fibers (stretch and recoil) Fibers project in all directions Functions include: Resist pull in all directions Provide strength and elasticity Note: Possesses various other cell types

PowerPoint Presentation: 

Sectional view of subcutaneous areolar connective tissue 1000x LM Skin Mast cell 400x LM Reticular fiber Elastic fiber Fibroblast Collagen fiber Subcutaneous layer Fibroblast Collagen fiber

Adipose Tissue : 

Adipose Tissue The most abundant cell type in this tissue= adipocytes These cells store triglycerides (fat), which serves as: Padding Insulation Energy Common locations: Subcutaneous layer Around heart and kidneys Between muscles

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Sectional view of adipose tissue. Fat is unstained or has been removed during the preservation process. Cytoplasm Fat-storage area Nucleus Note: the nuclei and cytoplasm have been shoved into the corners of the cells by the fat storage areas..

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Obviously, excess triglycerides can be stored as fat in the adipose tissue. However, excess carbohydrates and amino acids from protein can share the same fate. Watch what you eat. A Few Final Thoughts on Adipose Tissue

Reticular Connective Tissue : 

Reticular Connective Tissue Specialized fibroblasts called reticular cells produce an abundance of reticular fibers These cells form the stroma of the organ or gland

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Common locations for reticular connective tissue include: Lymph nodes Spleen Pancreas The fibers often have a jagged appearance (like lightning bolts)

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Sectional view of reticular connective tissue of a lymph node 400x LM Nucleus of reticular cell Reticular fiber Lymph node

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Again, note the jagged nature of many of the reticular fibers. They look like lightning bolts.

Dense Connective Tissues: 

Dense Connective Tissues Dense connective tissues include: Dense regular Dense irregular Elastic

Dense Regular Connective Tissue: 

Dense Regular Connective Tissue Primarily collagen fibers Fibers are arranged in an orderly pattern one direction layered like lasagna Located in the tendons and ligaments Resists pull in one direction

PowerPoint Presentation: 

Sectional view of dense regular connective tissue of a tendon Nucleus of fibroblast Collagen fiber Collagen fiber Tendon

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Dense Regular Artist’s Conception Nucleus of fibroblast Collagen fiber

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An additional view of dense regular connective tissue Collagen fibers arranged in orderly pattern

Dense Irregular: 

Dense Irregular Primarily collagen fibers Fibers have no orderly arrangement Resists pull in multiple directions Locations include: Deep layer of the dermis Heart valves Fibrous pericardium Perichondrium and periosteum

PowerPoint Presentation: 

Sectional view of dense irregular connective tissue of reticular region of dermis 640x LM 200x LM Blood vessel Collagen fiber (l.s.) Collagen fiber (t.s.) Nucleus of fibroblast Skin Dermis Note the longitudinal section (l.s.) and transverse section (t.s.) of the collagen fibers. Clearly, the fibers are oriented in multiple directions.

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Dense Irregular Artist’s Conception Collagen fiber (l.s.) Collagen fiber (t.s.) Blood vessel

Elastic Connective Tissue: 

Elastic Connective Tissue Primarily elastic fibers (often in bundles) Locations include: Elastic arteries (such as aorta) Lungs Allows for stretch and recoil

Two Views of Elastic Connective Tissue: 

Two Views of Elastic Connective Tissue Elastic fiber (bundle of fibers or elastic lamellae) Elastic fibers (individual fibers)

Cartilage: 

Cartilage Matrix includes: Gelatinous ground substance Collagen and elastic fibers Cells include: Chondroblasts Immature cells Produce cartilage Chondrocytes Mature cells Maintain cartilage Reside in openings called lacunae Lacunae containing chondrocytes

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Chondroblasts produce the cartilage These immature cells mature to become chondrocytes The chondrocytes reside in holes called lacunae Lacunae containing chondrocyte

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Three types of cartilage Hyaline cartilage Fibrocartilage Elastic cartilage

Hyaline Cartilage: 

Hyaline Cartilage Locations and functions include: Ends of long bones Reduces friction and absorbs shock Tracheal rings Holds trachea open Cartilage templates

Fibrocartilage: 

Fibrocartilage Locations and functions include: Intervertebral discs Cartilage pads in the knees Pubic symphysis All provide for: Shock absorption Some flexibility Note the presence of collagen fibers

Elastic Cartilage: 

Elastic Cartilage Locations include Ear flaps (auricles) Eustachian tubes Maintains shape and provides for flexibility Note the presence of elastic fibers

Help! How Do I Identify the Different Types of Cartilage? : 

Help! How Do I Identify the Different Types of Cartilage? Step one: Identify that the tissue is a form of cartilage Look for the lacunae and chondrocytes

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Step two: Look for visible fibers None visible= hyaline Bundles of thick fibers= fibrocartilage Many thin fibers= elastic Fine collagen fibers are not visible Thick collagen fibers Thin elastic fibers

Bone: 

Bone Bone cells are scattered in a matrix of minerals and fibers Minerals provide strength Fibers provide flexibility The matrix is solid Two types of bone tissue Spongy Compact

Compact Bone: 

Compact Bone Compact bone is composed of osteons (haversian systems) They look like old fashioned archery targets The “bullseye” is the central canal The scoring rings are rings of bone called concentric lamellae Central Canal Concentric lamellae

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1. 2. 1. Central canal 2. Concentric lamellae

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There are four types of bone cells Osteogenic Cells Give rise to osteoblast Osteoblast Produce bone Mature to become oseocytes Osteocytes Maintain bone Osteoclast Breakdown bone

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The cells typically observed in compact bone are osteocytes They are located in holes called lacunae Adjacent osteocytes are connected by cell extensions that pass through canaliculi

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Osteocyte in lacunae Canaliculi

Spongy Bone: 

Spongy Bone

Spongy Bone : 

Spongy Bone Note: no true osteons Trabeculae Spongy bone is composed of flakes of bone called trabeculae

Blood: 

Blood Surprise, blood is a tissue (connective tissue). The matrix is a liquid Plasma Cells include Erythrocytes= Red blood cells Leukocytes= White blood cells Thrombocytes= Platelets

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RBC WBC

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The plasma transports Various ions Nutrients Gases Waste products Plasma proteins RBCs primarily transport oxygen WBCs fight infection Platelets aid in clotting

Overview of Muscle and Nervous Tissue: 

Overview of Muscle and Nervous Tissue This exercise provides only a brief examination of muscle and nervous tissues They are addressed in more detail later in class

Muscle Tissue: 

Muscle Tissue Three types of muscle tissue Skeletal Cardiac Smooth

Skeletal Muscle: 

Skeletal Muscle Characteristics of skeletal muscle cells: Long and cylindrical Striated Voluntary Attached to bones Many nuclei (located at the periphery) Attached to bones Functions include: Movement and posture

PowerPoint Presentation: 

400x LM Longitudinal section of skeletal muscle tissue Skeletal muscle fiber (cell) Nucleus Note striations Skeletal muscle Skeletal muscle fiber

Cardiac Muscle: 

Cardiac Muscle Characteristics of cardiac muscle cells: Branched Striated Involuntary Presence of intercalated disks Typically have one nucleus (centrally located) Functions include: Pumps blood

PowerPoint Presentation: 

500x LM Longitudinal section of cardiac muscle tissue Nucleus Cardiac muscle fiber (cell) Intercalated disc Striations Cardiac muscle fibers

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Cardiac Muscle Central Nucleus Cells branch Intercalated discs

Smooth Muscle: 

Smooth Muscle Characteristics of cells: Spindle shaped (tapered) Single nucleus Locations include: Walls of hollow organs, vessels and airways Functions include: Peristalsis Constriction of vessels and airways Contraction of bladder

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500x LM Longitudinal section of smooth muscle tissue Nucleus of smooth muscle fiber Artery Smooth muscle fiber Note: cells taper

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Smooth Muscle Cells Note spindle shape

Two Types of Nervous Tissue: 

Two Types of Nervous Tissue Neuroglia (“nerve glue”) Cells that bind and support the neurons Some types are located in the CNS Others are found in the PNS Further details are addressed in later chapters Neurons Cells that produce, conduct and receive electrical impulses

PowerPoint Presentation: 

400x LM Neuron of spinal cord Dendrite Nucleus in cell body Axon Spinal cord

Neuron: 

Neuron Dendrites Nucleus Cell body

MEMBRANES: 

MEMBRANES Sheets of tissue that cover or line surfaces, separate organs or portions of organs Many produce secretions with a specific function Composed of epithelial tissue and connective tissue Epithelial Membranes 3 types of these Serous Mucous Cutaneous Serous membranes Line body cavities that do not open to the outside Wrap organs within these cavities Mucous Membranes Line body cavities that open to the outside The cutaneous membrane is also called the skin

PowerPoint Presentation: 

Pleural membranes secrete serous fluid that prevents friction when lungs expand and recoil, or when the heart beats. The parietal pleura wraps the inside of the thoracic cavity The visceral pleura wraps the surface of the lungs The heart has its own set of serous membranes that form the pericardium (discussed in detail in 169). The peritoneum is the serous membrane of the abdominopelvic cavity. The parietal peritoneum wraps the inside of the abdominopelvic cavity. The visceral peritoneum wraps the surface of the organs within this cavity. Forms the mesenteries. Serous Membranes

Mucous Membranes: 

Mucous Membranes Line the body cavities that have openings to the environment Examples: Respiratory tract Digestive tract Urinary tract Reproductive tract Surface of the eyes The type of epithelium (mucosa) of the membrane varies. The esophagus and vagina Stratified squamous Trachea Pseudostratified ciliated columnar Stomach Simple columnar The mucus secreted by this type of membrane: Keeps the lining lubricated Traps dust, bacteria, etc.

Cutaneous Membrane: 

Cutaneous Membrane The skin is commonly called the cutaneous membrane. It includes an epithelial tissue and connective tissue. The cutaneous membrane is discussed as part of the integumentary system.

Synovial Membranes: 

Synovial Membranes Synovial membranes form the inner lining of joint capsules. They are composed of loose connective tissue. These membranes are discussed as part of the appendicular skeleton.