Anatomy and Physiology Chapter 4 - Tissue Level of Organization PDF

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Chapter 4: The Tissue Level of Organization 4.1 Types of Tissues: name 4 types of tissues that make up human body and characteristics of each - Tissue – a group of cells that usually have a common embryonic origin and function together to carry out specific activities - 4 tissue types A. Epithelial  Lines all surfaces and hollow organs  Secrete and excrete B. Connective tissue  Protects and supports  Bind organs together, store energy, immunity C. Muscular  Contraction and force exertion  Generates heat D. Nervous  Detects changes inside/outside body  Generate electrical impulses 4.2 Cell Junctions: Describe the structure and function of the 5 main types of cell junctions - Cell junctions – contact points between plasma membrane of tissue cells - Types: o Tight Junctions  Seal off passageways between adjacent cells – impermeable barrier between cells  Transmembrane proteins fuse plasma membranes  Found in epithelium of stomach, intestines, bladder o Adherens junctions  Contain: plaque, microfilaments, integral mb proteins (cadherins)  Adherens junctions form extensive zones called adhesion belts  Adhere cells together so tissues can stretch o Desmosomes  Contain: plaque. Cadherins, intermediate filaments  Stabilizes tissue and cells  Found in epidermis, cardiac muscle cells  Prevent epidermal cell separation/disruption under tension o Hemidesmosomes  Resemble desmosomes – half a desmosome  Contains: integrins attach laminin and keratin, intermediate filaments  Anchor cells to basement membrane o Gap Junctions  Connexins (protein) form tunnels that connect to next cell – protein channel  Communication and transport

4.3 Comparisons between Epithelial and Connective Tissue: State the main differences between epithelial and connective tissue - Epithelial vs connective tissue A. Packed tissues vs scattered cells B. Little to no matrix vs large amount of matrix C. Avascular vs vascular 4.4 Epithelial Tissue: Describe general features of epithelial tissues and list the location, structure, and function of each different type of epithelial tissue - Epithelial Tissue (Epithelium) A. Densely packed layers B. Cover and lines surfaces C. Protects, secretes, absorbs, and excretes - Structure A. Apical surface – free surface B. Lateral surfaces – fact the adjacent cells C. Basal surface – opposite of apical surface D. Basement membrane – connects to cells by cell junctions E. Avascular; but does have nerve supply F. Mitosis occurs frequently - Classification A. Layers – simple vs pseudostratified vs stratified B. Cell shape – squamous vs cuboidal vs columnar vs transitional

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Two Types A. Covering/lining epithelium (surface epithelium)  Outer covering of skin and internal organs  Inner lining of blood vessels, ducts, body cavities, and interior of respiratory, digestive, urinary, and reproductive systems A. Simple Squamous Epithelium a. Single layer of flat cells b. Found in: i. cardiovascular and lymphatic vessels (endothelium) ii. epithelial layer of serous membranes (mesothelium) c. Help in filtration, diffusion, secretion B. Simple Cuboidal Epithelium a. Single layer of cube shaped cells b. Found: i. Covering surface of ovaries ii. Lines surface of capsule of eye, kidney tubules, and small ducts/glands iii. Pigmented epithelium of retina iv. Secreting portion of thyroid and ducts of pancreas c. Secretion and absorption C. Simple Columnar Epithelium (Nonciliated) a. Single layer of nonciliated column like cells i. Microvilli – fingerlike projects; increase surface area ii. Goblet cells – modified columnar epithelial cells that secrete mucus b. Found in: i. Lining of GI tract, ducts of glands, gallbladder c. Secretion and absorption i. Mucus lubricates linings – helps prevent destruction of lining D. Simple Columnar Epithelium (Ciliated) a. Single layer of ciliated column like cells b. Found in: i. Lining of bronchioles, uterine tubes, uterus, paranasal sinus, central canal of spinal cord, ventricle of brain c. Cilia moves mucus and foreign particles E. Pseudostratified Columnar Epithelium (Nonciliated) a. Appearance of several layers – single layered b. Found in: i. Airway of upper respiratory tract c. Secrete mucous; cilia sweeps away mucous F. Stratified Squamous a. Layered flat cells b. Found in i. Keratinized – skin

ii. Nonkeratinized – mouth, vagina, anus c. Protection G. Stratified Cuboidal Epithelium a. Layered cube-shaped cells b. Found in: i. Ducts of adult sweat and esophageal glands c. Protection; some secretion and absorption H. Stratified Columnar Epithelium a. Layered column like cells b. Found in: i. Parts of urethra ii. Esophageal glands c. Protection and secretion I. Transitional Epithelium (Urothelium) a. Variable appearance b. Found in: i. Urinary bladder ii. Portion of ureter and urethra c. Allows stretch and protective lining; hold fluid B. Glandular Epithelium  Gland – single cell or mass of epithelial cells adapted for secretion  Secreting portion of glands  Thyroid, adrenal, sweat, digestive  Unicellular – single cells  Goblet cells  Multicellular – many cells  Sweat glands  Oil glands  Salivary glands  A. Endocrine Glands a. Secretion enter interstitial fluid and diffuse into blood stream b. Ex: pituitary gland, pineal gland, thyroid, ovaries, testes, thymus c. Hormones regulate metabolism and homeostasis B. Exocrine Glands a. Secretion released into ducts that empty on to surface b. Ex: sweat glands, oil glands, earwax glands, salivary glands c. Produce substance to regulate temperature, oil, earwax, sweat, digestive enzymes

4.5 Connective Tissue: explain general features of connective tissue and describe structure, location, function of various types of connective tissue - Two elements: A. Cells B. Extracellular matric  Composed of fiber and ground substance  Fiber: o Collagen – strong flexible bundles of protein collagen o Reticular – collagen and glycoproteins; branching networks o Elastic – stretchable fiber; made of protein, elastin, fibrillin  Located in space between connective tissue cells  - Vascular and nerve supply EXCEPT for tendons and cartilage - Do not have free exposed surfaces -

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Types of cells: A. Fibroblasts – large flat cells  Secrete fibers and ground substance B. Macrophages – develop from monocytes  Destroy bacteria and cell debris by phagocytosis C. Plasma Cells – develop from B lymphocytes  Secrete antibodies D. Mast Cells – abundant along blood vessels  Produce histamine E. Adipocytes – fat cells  Store fats F. Eosinophils – white blood cells  Migrate to site of parasitic infection and allergic response G. Neutrophils – white blood cells  Migrate to site of infection that destroy microbe

Classification - Embryonic A. Mesenchyme  Irregular shaped mesenchymal cells; ground substance has reticular fibers  Found in:  Under the skin  Along developing bones of embryo  Some along blood vessel  Forms almost all other types of connective tissue B. Mucous (Mucoid) Connective Tissue  Widely scattered fibroblasts; jellylike ground substance contains collage fibers  Found in:  Umbilical cord of fetus  Support - Mature A. Loose  Areolar  Random fibers and cells; semifluid ground substance  Found in: o Every body structure o Subcutaneous layer deep ti skin o Papillary region of dermis o Blood vessels, nerves, organs  Strength, elasticity, support  Adipose Tissue  Cells derived from fibrocytes  Found in: o Subcutaneous layer deep to skin o Around heart and kidneys  Insulation, energy storage, support and protection  Reticular Connective Tissue  Interlacing network of reticular fibers  Found in: o Stroma of liver o Lymph nodes and spleen o Red bone marrow B. Dense  Regular Connective Tissue  Collagen regularly arranged in bundles with fibroblasts  Found in: o Tendons o Ligaments o Aponeuroses  Strong attachment between structures

Irregular Connective Tissue  Collagen fibers irregularly arranged with few fibroblasts  Found in: o Sheets beneath the skin o Joint capsules o Heart valves  Provides tensile strength in many directions  Elastic Connective Tissue  Predominantly elastic fibers  Found in: o Lung tissue, trachea, bronchial tubes o Wall of elastic arteries  Allow stretching of organs C. Cartilage  Dense network of collagen fibers and elastic fibers in chondroitin sulfate  Stronger and more resilient  Chondrocytes in lacunae  Avascular – grows and repairs slowly  Three types:  Hyaline Cartilage o Resilient gel substance; most abundant cartilage o Found in:  End of long bone  Ribs  Trachea, bronchi, bronchial tubes o Smooth surface of movement  Fibrocartilage o Chondrocytes among collagen fibers o Found in:  Pubic symphysis  Intervertebral discs  Menisci o Support and join structures together  Elastic Cartilage o Chondrocytes in threadlike network of elastic fibers o Found in:  Epiglottis  Auricle of ear  Auditory tubes o Provide strength and elasticity  Interstitial growth – chondrocytes divide to form new cells; occur in childhood and adolescence  Appositional growth – cells surrounding perichondrium differentiate to chondrocytes 

D. Bone     

Calcium salts in matrix with collagen fibers Osteocytes in lacuna Functions  Supports, protects, provides levers for muscular action, storage Hematopoiesis  Occurs in marrow inside bones Two types:  Compact/Dense (Haversian system/Osteon)  Spongy Bones (trabeculae/no osteon)

E. Blood  Liquid ground substance  Red blood cells, white blood cells  Found in blood vessels  Transport oxygen/carbon dioxide  Immune system response  Clotting 4.7 Muscular Tissue: describe the features of muscular tissue and compare structure, location, and control of different types of muscular tissue - Consists of fibers that provide motion, posture, and heat - Three types: o Skeletal muscle  Long, cylindrical striated fibers; voluntary  Found in:  Attached to bones by tendons  Motion, posture, heat production, protection o Cardiac muscle  Branched, striated fibers; single nucleus  Found in:  Heart wall  Circulation Smooth muscle  Nonstriated spindle-shaped fibers  Found in:  Iris of eyes  Hollow structure of blood vessels  Airway to lungs  Stomach, intestine, gallbladder, urinary bladder, uterus  Motion 4.8 Nervous Tissue: describe the structural features and function of nervous tissue - Two types: o Neurons  Cell body, dendrite, axon o

 Sensory and motor information Neuroglia  Protect and support neurons  Insulation 4.6 Membranes: define a membrane and describe the classifications of membranes - Membranes are flat sheets of pliable tissue that cover or line a part of the body o 2 types:  Epithelial  Mucous o Line cavities that open to outside  Serous membranes o Line cavities that do not open directly to outside  Cutaneous membrane o Covers the surface of the body  Synovial membrane  Found between joints 4.9 Excitable Cells: explain the concept of electrical excitability - Neurons and muscle fibers are excitable because they exhibit electrical excitability - Electrical excitability – ability to respond to certain stimuli by producing electrical signals 4.10 Tissue Repair – Restoring Homeostasis: Describe the role of tissue repair in restoring homeostasis - Tissue Repair – process to replace worn out, damaged, dead cells o Epithelial cells are replaced by division of stem cells/undifferentiated cells o Not all connective tissue cells have ability to repair o Muscle cells can perform limited repair o Some nervous cells can perform limited repair, other cannot - Regeneration – replacement by same type of tissue - Fibrosis – replacement by scar tissue - Homeostatic imbalances o Disorder of epithelium tend to be specific to organ (ulcers) o Disorders of connective tissues tend to be autoimmune in nature (lupus) 4.11 Aging and Tissues: describe the effects of aging on tissues - Younger bodies experience o Better nutritional state o Better blood supply to tissues o Faster metabolic rate - Aging slows process of tissue repair - Tissues stiffen and loose elasticity with aging o...