Histology notes - MARIEB PDF

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Summary

Here are some histology notes. The source is from Essentials of Anatomy and Physiology by Marieb...

Description

HISTOLOGY - Study of tissues of the body - tissues - group of cells with common function and structure ~~Sweat glands – epithelial -> cover surface of the body (forms ducts) ~~Heart is the only connective tissue

NERVOUS TISSUE - controls the body's movements, sends and carries signals to and from the different parts of the body, and has a role in controlling bodily functions Functions: • Irritability • Conductivity

NEURON CALSSIFICATION 

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Structural: Multipolar — three or more processes Bipolar — two processes (axon and dendrite) Unipolar — single, short process Functional: Sensory (afferent) —transmit impulses toward the CNS Motor (efferent) — carry impulses away from the CNS Interneurons (association neurons) — shuttle signals through CNS pathways

MUSCULAR - muscle contract that enables us to do physical activities - generates heat energy NERVOUS - neurons and nerve cells - interpretation gathered; transmits/receive info EPITHELIAL - lining -> skin, stomach = secrete materials - secretory -> releasing of hormones - line the cavities and surfaces of blood vessels and organs throughout the body. • Cellularity – composed almost entirely of cells • Special contacts – form continuous sheets held together by tight junctions and desmosomes • Supported by connective tissue – reticular and basal laminae • Regenerative – rapidly replaces lost cells by cell division - ability of the cell to rapidly replace the lost/dead cells

GENERAL CLASSIFICATION 1. 2.

Covering or lining tissue – these cells can be stratified (layered), ciliated or keratinized. Glandular or secretory tissue – these cells are specialized to secrete materials such as digestive tissues, hormones, milk, sweat, and wax. They are columnar or cuboidal-shaped.

simple epithelium (one layer of cells) stratified epithelium (more than one cell layer). > Reticular and Basal Laminae = epithelial and connective > mammary gland is a modified sweat gland > SPECIAL CONTACTS Tight Junction - make tissue impermeable to water; waterproof (kaya hindi nababasa yung skin natin kahit umuulan) Desmosomes - strong adhesion between cells

> CLASSIFICATION OF EPITHELIA TISSUE REPAIR • Wound healing • Two ways: 1. Regeneration- replace destroy tissue by same kind of cells 2. Fibrosis- form scar tissue (dense fibrous connective tissue) INFLAMMATION • WBC’s and clotting proteins seep into injured area • Clot prevent blood loss

EPITHELIUM - shape and no of layer

SHAPE

GRANULATION TISSUE FORMS • Delicate pink tissue with new capillaries • Connective tissue produces collagen fibers • Epithelial tissue multiply SURFACE EPITHELIUM REGENERATES • Surface epithelium thickens • Fibrous tissue matures forms scar

+ Squamous – flat, scale like Columnar - taller than wide

No. of Layer Simple – one layer only Pseudostratified – false stratification - looks like it has many layers but the truth is, it only has one layer *ang nagpapalinlang yung size/height of cell is different from one another Stratified – more layers

• PSEUDOSTRATIFIED COLUMNAR - secretion of mucus - rest on a basement membrane. - some of its cells are shorter than others, and their nuclei appear at different heights above the basement membrane. - gives the false (pseudo) impression that it is stratified - Like simple columnar epithelium, this variety mainly functions in absorption and secretion. - A ciliated variety (more precisely called pseudostratified ciliated columnar epithelium) lines most of the respiratory tract - goblet cells in this epithelium acts as a “sticky trap” to catch dust and other debris, and the cilia propel the mucus upward and away from the lungs. Upper Respiratory Tract / Trachea - cilia -> move mucus *depends on the temperature. If cold, the movement is slow kaya pag malamig, nangongongo. If mainit, mabilis ang movement

• SIMPLE SQUAMOUS EPITHELIUM - is a single layer of thin squamous cells resting on a basement membrane. - usually forms membranes where filtration or exchange of substances by rapid diffusion occurs. - it forms the walls of capillaries, where nutrients and gases pass between the blood in the capillaries and the interstitial fluid. - also forms serous membranes, or serosae = the slick membranes that line the ventral body cavity and cover the organs in that cavity. Lungs - air sacs / cross section of the lungs (alveoli) = where oxygen and carbon dioxide are exchanged - diffusion and filtration - exchange of gases - passive transport 1. Epithelium of aveoli 2. Passive transport -> diffusion

Bakit sa lungs nangyayari ang exchange of gas?

*blood contains iron that allows oxygen to go through the body

Ciliated - trachea

Non-Ciliated - male parts like vas deferens

• SIMPLE EPITHELIA - most concerned with absorption, secretion, and filtration • STRATIFIED EPITHELIA - consist of two or more cell layers - more durable than the simple epithelia, these epithelia function primarily in protection. • STRATIFIED SQUAMOUS EPITHELIUM - several layers of cells - Keratinized and Non-Keratinized - the most common stratified epithelium in the body - found in sites that receive a good deal of abuse or friction, such as the surface of the skin, the mouth, and the esophagus Keratinized - presence of keratin - dry membrane - feet, kalyo

Kidney Glomeruli - filtration *NEPHRONS – functional unit of kidney Lining of Heart • SIMPLE CUBOIDAL EPITHELIUM - which is one layer of cuboidal cells resting on a basement membrane, is common in glands and their associated small tubes called ducts (for example, the salivary glands and pancreas). - forms the walls of the kidney tubules and covers the surface of the ovaries. Kidney Tubules - secretion and absorption • SIMPLE COLUMNAR EPITHELIUM - made up of a single layer of tall cells that fit closely together. - presence/ non presence of cilia - lines the entire length of the digestive tract from the stomach to the anus - Epithelial membranes that line body cavities open to the body exterior is called mucosae (mu-ko′se), or mucous membranes. *Goblet cells - secretion of mucus -> prevents entry of contaminants - produce a lubricating mucus Ciliated - cilia in surface Lower Respiratory Tract/Bronchi *contaminants will be pushed upward by the cilia -> ciliated action - regions of uterine tube Non Ciliated - no cilia

Non-Keratinized - no keratin - moist/wet - mouth, throat, esophagus, vagina - always subjected to mechanic stress

• Stratified Cuboidal and Stratified Columnar Epithelia STRATIFIED CUBOIDAL EPITHELIUM - has just two cell layers with (at least) the surface cells being cuboidal in shape. STRATIFIED COLUMNAR EPITHELIUM - columnar cells, but its basal cells vary in size and shape. > these epithelia are fairly rare in the body, found mainly in the ducts of large glands.

• TRANSITIONAL EPITHELIUM - changes shape of the cell to increase the surface area - highly modified, stratified squamous epithelium that forms the lining of only a few organs—the urinary bladder, the ureters, and part of the urethra. > part of the urinary system - all of these organs are subject to considerable stretching * When the organ is not stretched, the membrane is many-layered, and the superficial cells are rounded and domelike. * When the organ is distended with urine, the epithelium thins like a rubber band being stretched, and the surface cells flatten and become squamous like. Urinary Bladder 1L of urine can be stored Ureter, Urethra

• GLANDULAR EPITHELIUM

Stomach to Anal Canal - participate for stomach to be safe - small intestine -> absorption - large intestine and anal -> lubricant Gall Bladder

Role of mucus

SECRETORY/ SECRETION - contains protein molecules in an aqueous (water-based) fluid. - active process in which the glandular cells obtain needed materials from the blood and use them to make their products, which then discharged by exocytosis

SIMPLE COLUMNAR EPITHELIUM Two major types of glands develop from epithelial sheets: > Endocrine - epithelial; ductless - Their secretions (all hormones) diffuse directly into the blood vessels Ex. thyroid, adrenals, and pituitary. > Exocrine - release of substances to ducts - secretions exit through the ducts to the epithelial surface. - include the sweat and oil glands, liver, and pancreas, are both internal and external. Ex. Mammary glands, sweat glands and salivary glands. • MUSCLE Skeletal - cylindrical - striated -> banded stripe appearance; the color is quite dark if there are structures present - multinucleated -> several nucleus per cell - action is voluntary *anus, mouth

PSEUDOSTRATIFIED SILIATED COLUMNAR EPITHELIUM

Smooth - spindle/ fusiform - no visible striation -uninucleated - action is involuntary *digestion Cardiac - quite similar to skeletal because they are both striated - branching cylindrical (passage of iron) - uninucleated - intercalated discs - action is involuntary *heart

SIMPLE AQUAMOUS EPITHELIUM STRATIFIED SQUAMOUS EPITHELIUM

SIMPLE CUBOIDAL EPITHELIUM

TRANSITIONAL EPITHELIUM...