Body Tissues PDF

Tissues of the Body By : Mr. Abubaker Elhemody  From Cells to Organ Systems  Cells combine to form tissues, and tissues combine to form organs.  Cells combine to form four primary tissues: 1. Epithelial tissue 2. Connective tissue 3. Muscle tissue 4. Nervous tissue ...

Tissues of the Body By : Mr. Abubaker Elhemody  From Cells to Organ Systems  Cells combine to form tissues, and tissues combine to form organs.  Cells combine to form four primary tissues: 1. Epithelial tissue 2. Connective tissue 3. Muscle tissue 4. Nervous tissue  Epithelium  Classification of epithelium  Two types: 1. Surface (membranous) epithelia Cover the external surface or line the cavities in the body. Two types:1) simple epithelium 2) stratified epithelium 2. Glandular epithelia Form 1) exocrine glands 2) endocrine glands  1. Membranous Epithelia 1. The simple epithelium (one layer of cells rest on basement membrane) mainly associated with lubrication, absorption or secretion function. It can be divided into: (1) Simple squamous epithelium (e.g. lung alveoli) (2) Simple cuboidal epithelium (e.g. renal tubules) (3) Simple columnar epithelium (e.g. intestinal inner-surface) (4) Pseudostratified (ciliated) columnar epithelium (respiratory epithelium) (e.g. trachea inner-surface) “ciliated” literally = eyelashes (see next page) 2. The stratified epithelium ( multi-layers contain deep, middle and superficial layers, only the basal cells rest on BM), mainly associated with protection function. Based on the shape of the surface cells, it can be divided into: (1)Stratified squamous epithelium: a) non-keratinized (e.g. esophageal inner-surface) b) keratinized (e.g. skin epidermis) (2) Stratified cuboid epithelium (e.g. ducts of sweat glands) (3) Stratified columnar epithelium (e.g. male urethra) (4) Transitional epithelium: (e.g. urinary bladder) relaxed  stretched Rare…  2. Glandular Epithelia Glands: Secretory structures derived from epithelia. Two Classes of Glands: Exocrine glands: Secretion (non hormonal) into a body surface (out of blood). Have ducts e.g. sweat ,salivary,….. Endocrine secretion: Secretion (of hormones) into blood Ductless glands e.g. pituitary, thyroid,……. Epithelial Functions 1. Protective 2. Absorption 3. Secretion 4. Excretion 5. Sensation  Connective Tissues Is formed by: Cells: Fibroblast (Production of fibers and ground substance) Mast cells, macrophages and plasma cells (defense) Adipose (fat) cells (storage of fats , heat production) Fibers: collagen, reticular and elastic fibers Ground substance: (glycosaminoglycans and proteoglycans)  Types of Connective Tissues 1. Connective tissue proper Loose C.T. e.g. found in the dermis and the hypodermis Dense C.T. – Regular e.g. tendons, ligaments – Irregular e.g. found in dermis 2. Connective tissues with special properties Adipose tissue e.g. under skin Blood: formed by: RBCs, WBCs, platelets + plasma Fluid C.T. Lymph: formed by: Lymphocytes (T&B) + lymph fluid 3. Supporting connective tissues Bone Cartilage  Loose Connective Tissue  Regular dense Connective Tissues  Adipose Tissue  Supporting Connective Tissue  Support the body.  Bone (osseous tissue) – Osteocytes + collagen fibers (type I)+ calcium salts. – Vascular (have blood vessels). – Covered by connective tissue called periosteum. – Have medullary cavity: contains bone marrow (forming blood). – Two types: (according to structure) 1. Compact bone 2. Spongy (cancellous) bone  2. Cartilage – Chondrocytes +collagen (type II) and elastic fibers+ chondriotin sulfate. – Avascular (have no blood vessels). – Covered by connective tissue called perichondrium. – Three types of cartilage: Hyaline cartilage ( e.g. articular cartilage, trachea, larynx) Elastic cartilage (e.g. Pinna of ear) Fibrocartilage (e.g. intervertebral discs)  Hyaline Cartilage A rticular cartilage: Covers articular surfaces  Elastic Cartilage Pinna of ear  Fibrocartilage Intervertebral disc Connective Tissue Functions 1. Structural framework 2. Fluid and solute transport 3. Physical protection 4. Tissue interconnection 5. Fat storage 6. Microorganism defense  Muscle Tissue Consists of specialized cells that contract when stimulated. The body has three types of muscle tissue: 1. Skeletal (voluntary)- attached to skeleton. 2. Cardiac (involuntary)- in heart. 3. Smooth muscle (involuntary)- in walls of hollow organs (viscera).  Nervous Tissue Contains specialized cells that conduct impulses (carries information).  Conducting cells, called neurons, transmit impulses from one region of the body to another.  Non-conducting cells, called glial cells, are a type of nervous system connective tissue (supporting cells).  Neuron (Nerve cell) Its parts: 1. Cell body 2. Dendrites(receives impulse) 3. Axon(send impulse)  Nervous Tissue: Support Cells of CNS 1. Astrocytes (nutrition) 2. Microglia (defense) 3. Ependymal cells (lining) 4. Oligodendrocytes Form myelin sheath in the central nervous system. Support Cells of the PNS 1. Satellite cells · Protect neuron cell bodies. 2. Schwann cells · Form myelin sheath in the peripheral nervous system. Figure 7.3e The End