Lecture 2 - Introduction To Histology PDF

CSI102 Histological Techniques LECTURE 2: INTRODUCTION TO HISTOLOGY NURHIDAYAH BINTI AB. RAHIM DIPLOMA IN MEDICAL LABORATORY TECHNOLOGY UNIVERSITI TEKNOLOGI MARA CAWANGAN PULAU PINANG KAMPUS BERTAM AT THE END OF LECTURE, STUDENT SHOULD BE ABLE...

CSI102 Histological Techniques LECTURE 2: INTRODUCTION TO HISTOLOGY NURHIDAYAH BINTI AB. RAHIM DIPLOMA IN MEDICAL LABORATORY TECHNOLOGY UNIVERSITI TEKNOLOGI MARA CAWANGAN PULAU PINANG KAMPUS BERTAM AT THE END OF LECTURE, STUDENT SHOULD BE ABLE TO: Classification and identification of the four primary tissues Characteristic features for identification of tissues in body systems 1. WHAT IS HISTOLOGY? web Histo tissue Branch of logy learning  1. WHAT IS HISTOLOGY? The science of the TISSUES Study of the cellular organization of body TISSUES AND ORGANS. IMPORTANCE OF HISTOLOGY - Establishing the significance of distinctive microscopic features of cell and tissues - Elucidate the relationship between microscopic structure and function 2 CLASSIFICATION AND IDENTIFICATION OF THE FOUR PRIMARY TISSUES A group of similar cells working together form tissues. More complex than cells A. EPITHELIUM A collection of adherent cells with very little intercellular material covering internal and external surfaces of body. Protection Absorption Smooth Secretion surfaces (sliding) CLASSIFICATION Simple squamous Stratified squamous epithelium epithelium Simple cuboidal Stratified cuboidal epithelium epithelium Simple columnar Stratified columnar Pseudostratified columnar epithelium epithelium epithelium  CLASSIFICATION – a. simple epithelium simple SIMPLE SQUAMOUS SIMPLE CUBOIDAL SIMPLE COLUMNAR epithelium tissue STRUCTU Single layer of flat Single layer of cube- Nucleus is oval, tall, RE (hexagonal cells) shaped cells, nuclei single layer of is large and centrally rectangular-shaped located. cells LOCATION Lining of blood and Glands and their Near the base, lines lymph vessels, small ducts, surface of the stomach, intestinal ducts, alveoli of lungs, ovaries, choroid tract, excretion ducts loop of Henle (Kidney plexus of the brain & gall bladder tubules), lining of serous membrane, inner of eardrum FUNCTION Diffusion, filtration, protection secretion, absorption secretion, absorption, against friction, secretion, protection absorption CLASSIFICATION – a. simple epithelium  CLASSIFICATION – b. stratified epithelium Stratified STRATIFIED STRATIFIED STRATIFIED epithelium SQUAMOUS CUBOIDAL COLUMNAR tissue STRUCTURE Main protective Many layers of cube- Multiple layers of epithelium, cells shaped cells cells, tall thin cells, gradually flattened, the nuclei are surface - large, oval- squamous shaped, located at basement membrane. LOCATION Oral cavity, vagina, Lining of sweat Mammary gland urethra glands, salivary gland duct, larynx, bile ducts duct, male urethra FUNCTION Protect underlying Secretion, absorption, Secretion, tissue protection against protection infection CLASSIFICATION – b. stratified epithelium CLASSIFICATION – c. Pseudostratified & transitional epithelium epithelium PSEUDOSTRATIFIED TRANSITIONAL tissue COLUMNAR CILIATED STRUCTURE Single layer of cells, attached to In dilated urinary bladder: the basement membrane, the - Two or three layer cells nuclei are at different levels and - Superficial layer is large and low cuboidal appear stratified, ciliated - Deeper layer is smaller and roughly cuboidal. In contracted bladder - Five or six layered cells - Convex free surface LOCATION Larynx, nasal cavity, pharynx, Pelvis of kidney auditory tubes, trachea, bronchi Ureter of the lungs Urinary bladder FUNCTION Movement of fluids (often mucus) Stretches readily & permit distention of urinary that contains foreign particles. organ by contained urine CLASSIFICATION – c. Pseudostratified & transitional epithelium Characterized by the presence of few cells but a large amount of intercellular substance Function: enclosing and separating organs connnecting tissues to one another (ligaments and tendons) supporting and moving (joints and cartilage) storing (adipose tissue and bones) cushioning and insulating (adipose tissues) transport and protection (blood) protection (cranium and sternum) Cells: Fibroblast, histocytes, plasma cells, mast cells, fat cells Connective tissue proper Fluid connective Supportive connective tissue tissue  a. Connective Tissue Proper (LOOSE CONNECTIVE TISSUE) a. Areolar b. Adipose c. Reticular Structure Cells within a fine network of mostly Entirely fat cells Consist of reticular collagen fibers Adipocytes or fat cells and reticular Loosely woven fibres in a semifluid cells contains fibres base. cytoplasm is pushed to the side of the cells Location - Between glands muscles and - Beneath - Liver nerves epidermis - Spleen - Attaches the skin to underlying - Around kidneys - Bone marrow tissues - Surface of colon - Lymphoid organs - Epithelial basement membrane Function - Loose packing - Packing material Reticular cells - Support tissues, organs, blood - Thermal insulator produce reticular vessels and nerves - Protection of fibres and have - For movement organs phagocyte qualities.  a. Connective Tissue Proper (DENSE CONNECTIVE TISSUE) a. Dense regular b. Dense irregular Structure i. Elastic tissue - In the form of sheet - Matrix composed of regularly - Mainly of collagenous fibres arranged collagen fibres and - Have elastic and reticular elastic fibres fibres - Fibres network - Between fibres, fibroblast and macrophages are found Location - Vertebrae - Dermis of skin - Neck - Capsules of liver , testes - Vocal cords and lymph nodes Function - Capable of stretching and Able to withstand tension recoiling exerted in many directions, provide structural strength  a. Connective Tissue Proper (DENSE CONNECTIVE TISSUE)  Collagen fibres – small and evenly dispersed in the matrix Growing long bones, cartilage rings of respiratory system, costal cartilage of ribs, nasal cartilage Hyaline Allow growth of long bones, provides flexibility Collagenous fibres, Fibres (> Cartilage numerous), arranged in thick bundles Fibrous Invertebral disk, articular disk (knee, jaw) Flexibility, Capable of withstanding Elastic considerable pressure External ear, epiglottis, auditory tubes Elastic fibres, > Opaque than Flexibility, lighweight support hyaline  Reticular framework, numerous blood forming cells Marrow Marrow cavities of bone, shaft of long bones, ends of long bones, in short flat and irregular bones Bones Produce new blood cells Hard bony matrix, osteocytes located within lacunae around central canals Outer portions of all bones, shafts of Compact long bones Great strength and support, forms solid outer shell on bones  Blood vessels Blood cells Transport oxygen, (erythrocytes & carbon dioxide, leukocytes) & nutrients, immune blood plasma, defense platelet Blood  Non striated Striated Cardiac Location Location Location Walls of hollow organs, iris Attached to bone. of eye, skin, glands Heart Functions (Involuntary) Functions Functions (Voluntary) (Involuntary) Regulates sizes of organs Movement of Pumps the blood Forces fluid through tubes body Control amount of light enter eyes Nervous tissue proper Supporting tissue Connective tissue Nerve cell (neuron) Neuroglia Large cells, Variety of shapes – variety of shapes, Makes capsule of many cells astrocytes, oligodendrocytes, ganglia, tubular process investments of ependymal cells, Schwann cells, nerves, meninges satellite cells, glial of brain cells Central nervous Brain, spinal cord system & Peripheral nervous system Conduct action To bind neurons potential together, supporting frame work for neurons Characteristic features for identification of tissues in body systems The CENTRAL NERVOUS SYSTEM is covered by specialized connective tissues that are divided into three layers: DURA MATER: the outer covering of the brain just inside the cranial cavity is a very tough layer of connective tissue--the dura. The potential space outside the dura next to the skull is known as the epidural space. The potential space beneath the dura between the dura and the brain is known as the subdural space. Histology of dura mater  ARACHNOID: this thin avascular connective tissue layer has irregular channels below it comprising the subarachnoid space, though which the cerebrospinal fluid accumulates. PIA: this thin layer of connective tissue is directly adjacent to the CNS. The pia and arachnoid are so close and so similar in structure that they are often called the pia-arachnoid, better known as the leptomeninges Ependymal Lining and Choroid Plexuses The cerebral ventricles and spinal canal containing the cerebrospinal fluid are lined by an ependyma, which consists of a single layer of cuboidal to columnar cells that have cilia or microvilli.  In the lateral ventricles and the fourth ventricle, the ependyma is specialized to form the choroid plexuses. These plexuses consist of a highly vascularized, arborizing stroma covered by cuboidal cells with fine microvilli. The choroid plexus produces approximately 0.5 to 1.5 liters of cerebrospinal fluid per day. This CSF is an ultrafiltrate of plasma that provides a "shock absorber" function for the brain. The CSF circulates through the ventricles and spinal canal. The CSF is reabsorbed at the arachnoid granulations at the vertex of the brain. If the flow of CSF is blocked, a condition known as hydrocephalus can occur. a single layer of cuboidal to columnar cells that have cilia or microvilli.  PERIPHERAL NERVOUS SYSTEM There are ganglia that are formed of a group of cell bodies. The dorsal root ganglia next to the spinal cord are involved with sensory function. The Schwann cells are specialized to form satellite cells that invest the cell bodies. The autonomic nervous system has autonomic ganglia that can be further divided into sympathetic and parasympathetic ganglia. The axons of neurons are typically grouped together to form nerve trunks. There are connective tissue layers that surround the peripheral nerves.  The peripheral nervous system has ganglia that consist of localized collections of nerve cell bodies surrounded by a connective tissue capsule. A ganglion provides a location for synapses. There are dorsal root ganglia adjacent to the spinal cord. There are ganglia associated with the autonomic nervous system known as parasympathetic and sympathetic ganglia. The actual sensory input into the periphral nervous system comes from a variety of specialized nerve endings and receptors. The sense of touch is one example. One of the largest, most impressive receptors is the pressoreceptor, or Pacinian corpuscle.