A&P Tissues

Tissue

groups of cells similar to structure and function.

Histology

the study of tissues.

Epithelial, Connective, Muscle, Nervous

4 tissue types that are the fabric of the body.

Epithelial

Continuous sheets of cells lining all external surface and internal cavities of an animal’s body.

Connective

Consist of one or more cell types embedded in a matrix and gives form to and anchors the organs of the body.

Muscle

elongate fibers specialized for contraction and movement of body parts.

Nervous

Receive, integrate, and transmit signals about internal and external stimuli.

Nervous tissue

Internal communication

Muscle tissue:

\n Contracts to cause movement

Epithelial tissue

Forms boundaries between different environments, \n protects, secretes, absorbs, filters

Connective tissue

Supports, protects, binds other tissues together

Brain, spinal cord, nerves

Where can you find nervous tissue?

\n \n • Muscles of heart (cardiac) \n • Muscles attached to bones (skeletal)

• Muscles of walls of hollow organs (smooth)

Where can you find muscle tissue?

\n \n • Glands (e.g., pancreas) \n • Lining of digestive tract organs and other hollow organs

• Skin surface (epidermis)

Where can you find Epithelial tissue?

• Tendons

• Bones

• Fat and other soft padding tissue

Where can you find Connective tissue?

Covering and Lining Form, Glandular Form

What are the two major forms of Epithelial Tissue

1. Protection
2. Absorption
3. Sensory reception
4. Excretion
5. Filtration

In Epithelial Tissue what are the 5 functions of Covering and Lining Form?

6. Secretion

In Epithelial Tissue is one function of Glandular Form?

Apical-basal polarity

one surface exposed to exterior or body cavity and one \n surface attached to basal lamina.

Tight Junctions and desmosomes

and keep epithelium as continuous sheets of cells.

1. Apical-basal polarity: one surface exposed to exterior or body cavity and one surface attached to basal lamina.

2. 2. Tight junctions and desmosomes keep epithelium as continuous sheets of cells.

3. 3. Always sit upon and supported by connective tissue (reticular lamina).

4. 4. Avascular, but innervated.

   1. 5.High regenerative capacity.

What are the Characteristics of Epithelial tissue

reticular lamina

Always sit upon and supported by connective tissue

how to classify epithelial tussue

• 1st name = # of layers, 2nd name = shape

types of epithelial tissue layers

Simple \n Pseudostratified \n Stratified

types of epithelial tissue shape

Squamous \n Cuboidal \n Columnar

simple squamous Epithelium

•1 layer; flattened and scale-like; polygonal in shape from a surface view; flattened nucleus.

• Found in areas of low abrasion and high diffusion.

• Involved in passage of materials where little or no protection is needed.

• Endothelium and Mesothelium

capillaries, alveoli, glomeruli

where can you find Simple Squamous Epithelium?

Simple Cuboidal Epithelium

• 1 layer; cube-shaped with a centrally placed nucleus.

• Function in both secretion and absorption.

kidney tubules, ducts of glands, seminiferous tubules

Where can you find Simple Cuboidal Epithelium?

Simple Columnar Epithelium

•1 layer; column-shaped; basally placed elongated nucleus.
• Function in secretion and absorption.
• Tend to be ciliated, thus allowing for movement of materials.
• Two major modifications in the digestive tract:

1. microvilli
2. goblet cells that secrete mucus

• Microvilli
• goblet cells that secrete mucus

What are two major modifications in the digestive tract

• digestive tract,
• oviducts,
• ducts of glands,
• uterus

Where can you find Simple Columnar Epithelium

Pseudostratified Columnar Epithelium

• 1 layer, but appears to be multiple because cell nuclei are at different levels.

• Short, non-functional cells give rise to taller functional cells.
• • Function in secretion.
• • Tend to be ciliated, thus allowing for movement of materials.
• • Modified goblet cells secrete mucus.

upper respiratory tract, vas deferentia, epididymides

Where can you find Pseudostratified Columnar Epithelium

Stratified Squamous Epithelium

• Multiple layers of squamous cells.

• Most widespread of the stratified epithelia.

• Found in areas of high abrasion where it serves a protective function.

• Cells produced in the deeper layers by cell division, are pushed towards the surface where they become flatter. Stratified Squamous Epithelium

• Keratinized cells form at the outermost layer of the skin.

skin, lips, mouth, vagina, rectum

Where can you find Stratified Squamous Epithelium

Keratinized

cells form at the outermost layer of the skin

Stratified Cuboidal Epithelium

• 2 layers of cuboidal cells.

• Enhances the durability and structure of glands.

salivary glands, sweat glands, mammary glands)

Where can you find Stratified Cuboidal Epithelium

pharynx, urethra, epithelial transition zones)

Where can you find Stratified Columnar Epithelium

Stratified Columnar Epithelium

• Multiples layers of columnar cells.

• Functions in durability and protection.

Transitional Epithelium

• Multiple layers (varies from ≈ 6 to 3 layers depending on degree of distension)

• Basal cells are cuboidal (distended) or columnar (not distended).

• Apical cells are squamous-like (distended) or dome-shaped (not distended).

• Stretching is caused by the hollow urinary organs filling with urine.

ureters, urinary bladder, urethra

Where can you find Transitional Epithelium

Epithelium is the Basis for Glands

• One or more cells that make and secrete an aqueous fluid (secretion).

• Classified based on where the secretion is released. endocrine, exocrine

• Can be unicellular (i.e., goblet cells) or multicellular (i.e., glands)

Endocrine

Secrete into the blood (hormones) ductless

Exocrine

Secrete into a body cavity (enzymes) or onto the skin (sweat) ducts are present.

• Connective Tissue Proper
• Cartilage
• Bone
• Blood

What are the four major classes of Connective Tissue

• Binding and Support
• Protection
• Insulation
• Energy Storage
• Transport

5 major functions of Connective Tissue

• Binding and Support
• protection
• insulation
• energy storage

Functions of Connective Tissue Proper

• Binding and support
• Protection

Functions of Cartilage

Mesothelium

lining that covers body cavity

Endothelium

Simple squamous that covers blood vessel

• Binding and support
• protection
• energy storage

Function of bone

• Protection
• Transport

Function of blood

1. All tissue arises from mesenchymal cells.
2. tissue can be avascular, poorly vascularized, or richly vascularized.
3. Mostly non-living extracellular matrix, which separates living cells of the tissue.

Characteristics of Connective Tissue

mesenchymal cells

stem cells that give rise to all different types of cells.

ground substance

• Fluid based.

• Most of the time it is gel-like because of cell adhesion proteins and proteoglycans.

Fibers

Provide the support

Collagen

• Cross-linked fibrils form thick fibers
• high tensile strength

Elastic

• Network of long, thin fibers of elastin
• stretchable and great recoil ability

Reticular

• delicate network of short fine fibers
• continuous with collagen fibers.

-blasts

immature cells produce ground substance and fibers of the matrix. (making cells)

-cytes

mature cells maintain the health of the matrix (monitoring it)

Connective tissue proper: Loose

• Most common type of connective tissue in vertebrates.

• Characterized by having a lot of open (“loose”) space.

• Vascularized.

Areolar, Adipose, Reticular

Types of Connective Tissue Proper: Loose

Areolar connective tissue

• Can clearly see the 3 fiber types - collagen (thicker, more rigid), elastin (thinner, stretchable), and reticular.

• Nuclei of fibroblasts (produce the fibers) can be seen.

• All in a gel-like matrix.

• Surrounds/cushions organs, blood vessels, nerves, glands, and forms subcutaneous tissue.

• Holds interstitial fluid and plays a role in \n inflammatory response.

• collagen (thicker, more rigid),
• elastin (thinner, stretchable),
• reticular.

What are the three types of fibers in Areolar Connective Tissue

Adipose Tissue

• Very few fibers and sparse extracellular matrix.
• Made up of large adipocytes that store fat globules.
• Nuclei pushed to outer edges of the cell to allow for maximum fat storage.
• Primarily lipid storage, but also functions in protection and insulation.
• In abdominal cavity, subcutaneous tissue, breasts, and around kidneys.

Adipose tissue

what tissue is primary for lipid storage but also function in protection and insulation

abdominal cavity, subcutaneous tissue, breasts, and around kidneys.

found in adipose

Where can you find Adipose Tissue

Surrounds/cushions organs, blood vessels, \n nerves, glands, and forms subcutaneous tissue.

• found around organs

Where can you find areolar connective tissue

Reticular Tussue

• Resembles areolar tissue, but the only fibers are reticular.
• Reticular cells (type of fibroblast) are scattered among fibers.
• Also tend to be able to see red blood cells.
• Forms a labyrinth-like internal framework that supports free blood \n cells in the lymph nodes, spleen, and red bone marrow.

Red blood cells with some tissue

What will you see in Reticular tissue

Connective Tissue Proper: Dense

• Characterized by having very little open (“dense”) space. \n • Fibers are prominent element… fibrous connective tissue. \n • Poorly vascularized.

• Regular
• Irregular
  • Elastic

Types Connective Tissue Proper: Dense

Dense Regular Connective Tissue

• Tight, regular arrangements of collagen fibers \n with fibroblasts in between. \n • Regular arrangement allows for high resistance to \n tension, while waviness allows for some “give”. \n • Mostly collagen fibers, but ligaments have more \n elastin fibers intermingled. \n • Tendons: muscle to bone. \n Ligaments: bone to bone. \n Fascia: fibrous membrane around muscles, \n vessels, and nerves.

Tendon

muscle to bone

Ligaments

bone to bone

fascia

fibrous membrane around muscles, vessels, and nerves

Dense Irregular Connective Tissue

• Same elements as the regular type, except collagen fibers are thicker and \n arranged irregularly. \n • Found in areas where tension is exerted from all directions \n (dermis, synovial joint capsules, organ capsules).

• Found in areas where tension is exerted from all directions \n (dermis, synovial joint capsules, organ capsules).

Where is Dense Irregular Connective Tissue found

Elastic Connective Tissue

• Mostly elastin fibers that look like squiggly dark lines. \n • High distension and recoil abilities.

• Maintains blood flow through elastic arteries and allows lungs to stretch and recoil with relative ease.

Cartilage

• Withstands tension and compression (tough, but flexible).
• Avascular and lacks nerves.
• Cartilagenous matrix is made by \n chondroblasts until puberty.

80%

Cartilage is made up of ___% water

Cartilagenous matrix is made by

chondroblasts until puberty

• Hyaline Cartilage
• Elastic Cartilage
• Fibrocartilage

What are the three types based on fiber composition and extracellular matrix

Hyaline Cartilage

most abundant, high amount of collagen; precursor to bones; found where flexibility is important

Elastic Cartilage

nearly identical to hyaline except it’s high in elastin; found where flexibility is important.

Fibrocartilage

high in collagen, yet many chondrocytes; resist tension, but is compressible; found where strong support and ability to withstand pressure is required

Bone (osseous tissue)

• Calcified (mineral salts) matrix with many collagen fibers.
• Highly vascularized and innervated.
• Exceptional protection/support for organs and muscles.
• Hematopoiesis.
• Mineral & fat storage.

Osteoblast

produces the fibers of the matrix; salts are deposited

Blood (Vascular Tissue )

Most atypical connective tissue.

Blood plasma

fluid matrix that contains blood \n clotting proteins (fibrinogen = fibers); transports \n nutrients, wastes, hormones, gases, and water.

1. Leukocytes (WBCs)
2. Erythrocytes (RBCs)
3. Platelets

Three main types of cellular elements for blood (Vascular Tissue)

Leukocytes (WBCs):

small % of blood volume; 5 major types; immune function.

Erythrocytes (RBCs)

biconcave discs; nucleated in all animals except mammals; contain hemoglobin to carry O2 & CO2.

Platelets

non-nuclear bodies derived from fragmentation of larger cells; blood clotting.

Muscle Tissue

• Highly vascularized and innervated.

• Made up of elongate muscle fibers (myocytes) specialized for contraction.

• Muscle fibers contain myofibrils, which contain the contractile filaments, actin and myosin.

Nervous Tissue

• Main component of the nervous system.
• Neurons are characterized by having a cell body with a series of processes, \n called dendrites and axons.
• Neurons detect stimuli, conduct action potentials, and generate a response.
• Glial cells are non-conducting cells that support, insulate, and protect

Neurons

____ are characterized by having a cell body with a series of processes, called dendrites and axons.