Description of Tissue | Study notes Anatomy

ANATOMY AND PHYSIOLOGY LECTURE - Tissue

Doc. Milliem Reyes|1st Semester | BSMLS-1K

TYPES OF TISSUES AND THEIR ORIGINS

1. Epithelial tissue covers body surfaces

and lines hollow organs, body cavities,

and ducts. It also forms glands.

2. Connective tissue protects and supports

the body and its organs. Various types of

connective tissue bind organs together,

store energy reserves as fat, and help

provide immunity to disease-causing

organisms.

3. Muscular tissue generates the physical

force needed to make body structures

move and generates body heat.

4. Nervous tissue detects changes in a

variety of conditions inside and outside

the body and responds by generating

action potentials (nerve impulses) that

activate muscular contractions and

glandular secretions.

CELL JUNCTIONS

Contact points between the plasma membranes

of tissue cells.

● TIGHT JUNCTIONS (Zonula occludens)

○ consist of weblike strands of

transmembrane proteins that

fuse the outer surfaces of

adjacent plasma membranes

together to seal off passageways

between adjacent cells

○ establishing cell polarity

○ lateral communication

● ANCHORING JUNCTION

○ Adherens ( Zonula adherens)

○ contain plaque, a dense layer of

proteins on the inside of the

plasma membrane that attaches

both to membrane proteins and

to microfilaments of the

cytoskeleton

○ Desmosomes (macula

adherens)

■ Lateral or side anchoring

membrane

○ Hemidesmosomes

■ anchoring basements

membrane

● GAP JUNCTION

○ Prominent in cardiac muscle

○ Helps the cell communicate and

synchronize

○ At gap junctions, membrane

proteins called connexins form

tiny fluid-filled tunnels called

connexons that connect

neighboring cells

EPITHELIAL TISSUE

➢ Cells arranged in a continuous sheet

➢ Closely packed cells

➢ Serve as a selective barrier that limits or

aids the transfer of substance into and

out of the body.

➢ A secretory surface that releases

products produced by the cells

➢ A protective surface that resists the

abrasive influences of the environment

SURFACES OF EPITHELIAL CELLS

● Apical

○ (free) surface of an epithelial cell

faces the body surface, a body

cavity, the lumen (interior space)

of an internal organ, or a tubular

duct that receives cell secretions

● Basal

○ of an epithelial cell is opposite

the apical surface, and the basal

surfaces of the deepest layer of

cells adhere to extracellular

materials.

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ANATOMY AND PHYSIOLOGY LECTURE - Tissue

Doc. Milliem Reyes|1st^ Semester | BSMLS-1K

TYPES OF TISSUES AND THEIR ORIGINS

Epithelial tissue covers body surfaces and lines hollow organs, body cavities, and ducts. It also forms glands.
Connective tissue protects and supports the body and its organs. Various types of connective tissue bind organs together, store energy reserves as fat, and help provide immunity to disease-causing organisms.
Muscular tissue generates the physical force needed to make body structures move and generates body heat.
Nervous tissue detects changes in a variety of conditions inside and outside the body and responds by generating action potentials (nerve impulses) that activate muscular contractions and glandular secretions. CELL JUNCTIONS Contact points between the plasma membranes of tissue cells. ● TIGHT JUNCTIONS (Zonula occludens) ○ consist of weblike strands of transmembrane proteins that fuse the outer surfaces of adjacent plasma membranes together to seal off passageways between adjacent cells ○ establishing cell polarity ○ lateral communication ● ANCHORING JUNCTION ○ Adherens ( Zonula adherens) ○ contain plaque, a dense layer of proteins on the inside of the plasma membrane that attaches both to membrane proteins and to microfilaments of the cytoskeleton ○ Desmosomes (macula adherens) ■ Lateral or side anchoring membrane ○ Hemidesmosomes ■ anchoring basements membrane ● GAP JUNCTION ○ Prominent in cardiac muscle ○ Helps the cell communicate and synchronize ○ At gap junctions, membrane proteins called connexins form tiny fluid-filled tunnels called connexons that connect neighboring cells EPITHELIAL TISSUE ➢ Cells arranged in a continuous sheet ➢ Closely packed cells ➢ Serve as a selective barrier that limits or aids the transfer of substance into and out of the body. ➢ A secretory surface that releases products produced by the cells ➢ A protective surface that resists the abrasive influences of the environment SURFACES OF EPITHELIAL CELLS ● Apical ○ (free) surface of an epithelial cell faces the body surface, a body cavity, the lumen (interior space) of an internal organ, or a tubular duct that receives cell secretions ● Basal ○ of an epithelial cell is opposite the apical surface, and the basal surfaces of the deepest layer of cells adhere to extracellular materials.

● Lateral Surface ○ epithelial cell face the adja cent cells on either side. AVASCULAR ● Epithelial tissue has its nerve supply but is avascular ○ Lack of blood supply ○ Rely on diffusion ○ it heals faster if there is blood vessel BASEMENT MEMBRANE a thin extracellular layer that commonly consists of two layers: the basal lamina and reticular lamina. ● Basal Lamina - is closer to— and secreted by—the epithelial cells. It contains proteins such as laminin and collagen. ● Reticular lamina- closer to the underlying connective tissue and contains proteins such as collagen produced by connective tissue called dibroblasts TWO TYPES OF EPITHELIAL TISSUE

1. Covering and lining epithelium ○ forms the outer covering of the skin and some internal organs. It also forms the inner lining of blood vessels, ducts, and body cavities, and the interior of the respiratory, digestive, urinary, and reproductive systems. ○ Arrangement of cells in layers. ○ **Cell shapes.

Glandular epithelium** ○ makes up the secreting portion of glands such as the thyroid gland, adrenal glands, and sweat glands. CLASSIFICATION OF EPITHELIUM SIMPLE EPITHELIUM ● SIMPLE SQUAMOUS ○ This tissue consists of a single layer of flat cells that resembles a tiled floor when viewed from the apical surface ○ Filtration, diffusion, osmosis, and secretion in serous membranes. ○ lines the heart, blood vessels, and lymphatic vessels are known as the endothelium ● SIMPLE CUBOIDAL ○ cube-shaped cells ○ found in organs such as the thyroid gland and kidneys and performs the functions of secretion and absorption ● SIMPLE COLUMNAR ○ it is ⅓ of the esophagus ○ may have goblet cells (produce mucus for lubrication and protection) ○ may appear like columns (taller than they are wide), with oval nuclei near the base. ● PSEUDOSTRATIFIED COLUMNAR ○ rest on the basement membrane ○ may have cilia for the movement of fluid and trapping debris or stereocilia, immobile ○ when viewed from the side, these features give the false impression of a multilayered tissue—thus the name pseudostratified epithelium ○ Secretion and movement of mucus by ciliary action. STRATIFIED ● STRATIFIED SQUAMOUS ○ ⅔ of the esophagus

and neutralize foreign substances

5. Macrophages a. are phagocytes that develop from monocytes, a type of white blood cell. 6. Leukocytes (White blood cells) a. certain conditions, they migrate from the blood into connective tissues. EXTRACELLULAR MATRIX ➢ the material located between its widely spaced cells ➢ Contain ground substance and fibers, the material between the cells and the fibers ➢ are secreted by the connective tissue cell and account for many of the functional properties of the tissue in addition to controlling the surrounding watery environment via specific proteoglycan molecules ➢ fibers in the ECM GROUND SUBSTANCE ● is the component of a connective tissue between the cells and fibers ● It supports cell fibers, binds them together, and provides a medium for exchanging substances between blood and cells. ● Collagen fibers are strong, flexible collagen bundles, the most abundant protein in your body. ● Elastic fiber : elasticity, plentiful in the skin, blood vessel walls, and lung tissue. ● Reticular fibers are made of collagen and glycoproteins. They support blood vessel walls and form branching networks around various cells (fat, smooth muscle, nerve). CLASSIFICATION OF CONNECTIVE TISSUE EMBRYONIC CONNECTIVE TISSUE A. Mesenchyme a. Forms all other types of connective tissue. Primarily present in the embryo B. Mucous (mucoid) connective tissue a. Support. (Umbilical cord of fetus) MATURE CONNECTIVE TISSUE LOOSE CONNECTIVE TISSUE ➢ loosely intertwined between cells. The types of loose connective tissue are areolar connective tissue, adipose tissue, and reticular connective tissue. ➢ Softer with more cells fewer fibers compared to others ● Areolar Connective Tissue ○ the most widely distributed connective tissue in the body, ○ forms the subcutaneous layer, the layer of tissue that attaches the skin to underlying tissues and organs. ○ lies under epithelial ● Adipose tissue ○ predominantly made of adipocytes (fat cells) ○ stores fat, isolate,s and protect organs ● Reticular tissue ○ fine interlacing reticular fibers and reticular cells ○ forms the stroma (supporting framework) of the liver, spleen, and lymph nodes and helps bind together smooth muscle cells. ● Vascular tissue ○ Blood cells DENSE CONNECTIVE TISSUE ➢ Dense fibrous tissue and collagen fiber

➢ contains more numerous, thicker, and denser fibers (packed more closely) but considerably fewer cells than loose connective tissue. ● Dense regular Connective tissue ○ found in tendons or muscles, ○ bundles of collagen fibers are regularly arranged in parallel patterns that provide the tissue with great strength ● Dense irregular Connective tissue ○ found in the dermis or skin ○ irregularly arranged, pulling forces are exerted in various directions, ● Elastic Connective tissue ○ artery, the heartbeat needs elasticity to continue beating ○ Branching elastic fibers pre-dominate in elastic connective tissue CARTILAGE ➢ Less rigid and more flexible than bone ➢ The strength of cartilage is due to its collagen fibers, and its resilience (ability to assume its original shape after deformation) is due to chondroitin sulfate. ● Hyaline cartilage ○ most abundant cartilage in the body but the weakest among the three types of cartilage. ○ It provides flexibility and support and, at joints, reduces friction and absorbs shock ○ common during fetal development ● Fibrocartilage ○ highly compressible ○ dound in intervertebral disc ○ cushioning support in the spinal column ○ Fibrocartilage lacks a perichondrium. With a combination of strength and rigidity, ○ strongest of the three types of cartilage. ● Elastic Cartilage ○ perichondrium is present. Elastic cartilage provides strength and elasticity and maintains the shape of certain structures (external ear). BONE OSSEOUS TISSUE ➢ made up of osteocytes in cavities(lacunae) stored calcium and phosphorus ➢ classified as compact or spongy, depending on how its extracellular matrix and cells are organized. MUSCULAR TISSUE ➢ Contraction to produce movement ➢ consists of elongated cells called muscle fibers or myocytes that can use ATP to generate force ● Skeletal muscle ○ Long cylindrical, multinucleate cells ○ the feature is its striations, alternating light and dark bands within the fibers visible under a light microscope. ○ voluntary controls ● Cardiac Muscle ○ Found only in your heart, involuntary ○ started, uninucleate; branching, gas junction to form syncytia ● Smooth muscle ○ No visible striation, involuntary ○ found in hollow movements to change cavity size and propel substance ○ slower contraction, there is gap junctions ○ Peristalsis- a series of muscle contractions. NERVOUS TISSUE ● Characterized by the ability to conduct electrical signals called action potentials. ● Found in the brain, spinal cord, and nerves ● Responsible for coordinating and controlling

Description of Tissue, Study notes of Anatomy

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