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[Audio] Topic 2: Levels of Organisation Lecture 3 : Levels of Organisation Learning Outcomes:  Describe cells and their levels of organisation  List the four major tissue types  Describe anatomy and histology of the basic cell/tissue types: - Epithelial, connective, muscle, neural.

[Audio] The Cell A cell is the basic unit of all living things. – Prokaryotic cells are simple cells that are Pro ("before") karyon ("nucleus") – they have no nucleus. Most are unicellular bacteria. – Eukaryotic cells are complex cells with a nucleus and subcellular structures (organelles). All fungi, plants, and animals are eukaryotes..

[Audio] A Generalized Cell. A Generalized Cell.

[Audio] Plasma Membrane Serves as the interface between the machinery in the interior of the cell and the extracellular fluid (ECF) that bathes all cells..

[Audio] The lipids in the plasma Plasma Membrane membrane are chiefly phospholipids. – The hydrocarbon tail is hydrophobic; – its polar head is hydrophilic. As the plasma membrane faces watery solutions on both sides, its phospholipids accommodate this by forming a phospholipid bilayer with the hydrophobic tails facing each other..

[Audio] Cytoplasm – Two components 1. Cytosol Intracellular fluid, surrounds the organelles The site of many chemical reactions (various dissolved & suspended components) Energy is usually released by these reactions Reactions provide the building blocks for cell maintenance, structure, function and growth 2. Organelles Membrane-enclosed structures within the cell Each perform different functions.

[Audio] Nuclear envelope - a double membrane that separates the nucleus from the cytoplasm Nuclear pores - numerous openings in the nuclear envelope, control movement of substances between nucleus and cytoplasm Nucleolus - spherical body that produces ribosomes.

[Audio] Lecture 3 : Levels of Organisation Learning Outcomes:  Describe cells and their levels of organisation  List the four major tissue types  Describe anatomy and histology of the basic cell/tissue types: - Epithelial, connective, muscle, neural.

[Audio] What is a Tissue? A tissue is a group of cells – Common embryonic origin – Function together to carry out specialized activities Hard (bone), semisolid (fat), or liquid (blood) Histology is the science that deals with the study of tissues. Pathologist specialized in laboratory studies of cells and tissue for diagnoses.

[Audio] (a) Epithelial Covers body surfaces and lines hollow organs, body cavities, duct, and forms glands –interact with internal and external environment (b) Connective Protects, supports, and binds organs. Stores energy as fat, provides immunity (c) Muscular Generates the physical force needed to make body structures move and generate body heat (d) Nervous Detect changes in body and responds by generating nerve impulses.

[Audio] Epithelial Tissues Epithelial tissue consists of cells arranged in continuous sheets. Surfaces of epithelial cells differ in structure and have specialized functions Apical (free) surface – Faces the body surface, body cavity, lumen, or duct Lateral surfaces – Faces adjacent cells Basal surface – Opposite of apical layer and adhere to extracellular materials.

[Audio] Two Main Types of Epithelium 1. Covering and lining epithelium –Outer covering of skin and some internal organs 2. Glandular epithelium –Secreting portion of glands (thyroid, adrenal, and sweat glands).

[Audio] Covering and Lining Epithelium Normally classified according to: Arrangement of cells into layers Shapes of cells.

[Audio] Different Types of Covering and Lining Epithelium Simple Simple squamous epithelium Simple cuboidal epithelium Simple columnar epithelium (nonciliated and ciliated) Pseudostratified columnar epithelium (nonciliated and ciliated) Stratified (two or more layers of cells) Stratified squamous epithelium Stratified cuboidal epithelium Stratified columnar epithelium Transitional epithelium Specific kind of stratified epithelium depends on the shape of cells in the apical layer.

[Audio] Summary of Covering and Lining Epithelium Endothelium lines the heart, blood vessels, and lymphatic vessels Mesothelium serous membranes such as the Simple squamous epithelium pericardium, pleura, or peritoneum Found in thyroid gland, pancreas and kidneys Simple cuboidal epithelium GI tract, ducts of glands, gallbladder Simple columnar epithelium Respiratory tract Ciliated Simple columnar epithelium.

[Audio] Summary of Covering and Lining Epithelium Trachea Pseudostratified columnar epithelium Stratified squamous epithelium Skin, mouth, esophagus Duct of esophageal gland (rare) Stratified cuboidal epithelium Pharynx (rare) Stratified columnar epithelium.

[Audio] Summary of Covering and Lining Epithelium Urinary tract Transitional epithelium.

[Audio] Glandular Epithelium Glands = cells or groups of cells that secrete substances G.E. is composed of cells that are specialized to produce & secret substances into ducts/body fluids. i. Endocrine glands Secret the interstitial fluid & then diffuse directly into the blood stream (without duct) Pituitary, thyroid & adrenal glands ii. Exocrine glands Secret products into ducts that empty onto the surface of a covering & lining epithelium Sudoriferous, salivary glands.

[Audio] Glandular Epithelium Endocrine glands Exocrine glands.

[Audio] Structural Classification of Exocrine Glands Unicellular glands = goblet cells Multi-cellular glands are categorized according to two criteria: – Ducts are branched or unbranched – Shape of the secretory portion of the gland.

[Audio] Epithelial membranes Membranes are flat sheets of pliable tissue that cover or line a part of the body. i. Epithelial membranes are a combination of an epithelial layer and an underlying connective tissue layer: Mucous, Serous, and Cutaneous membranes. ii. Synovial membranes Lines joints and contains connective tissue but not epithelium..

[Audio] Synovial Membrane – Lines the cavities of freely movable joints. Do not open to exterior. – Consist of discontinuous layer of non epithelial cells called synoviocytes. These secrete synovial fluid which lubricates the joint and also contains macrophages to remove debris and microbes..

[Audio] Connective Tissue Most abundant and widely distributed tissues in the body. Collagen – main protein of connective tissue. – most abundant protein in the body. (about 25% of total protein content). Connective tissue is usually highly vascular. Supplied with many nerves. The exception is cartilage and tendon. Both have little or no blood supply and no nerves..

[Audio] Components of Connective Tissue Connective tissue is made up of two components: 1. Sparse cells. 2. Extracellular matrix (ECM). Cell ECM.

[Audio] Cells Of Connective Tissues Cells of connective tissue are of mesodermal origin. Fibroblasts – Secrete protein fibers (collagen, elastin, & reticular fibers) and components of ground substance, most numerous..

[Audio] Cells of Connective Tissues Of the other common connective tissue cells: – Chondrocytes make the various cartilaginous connective tissue. – Adipocytes store triglycerides. – Osteocytes make bone. – White blood cells are part of the blood..

[Audio] Extracellular Matrix (ECM) of Connective Tissues ECM – a non-cellular material located between and around the cells. Extracellular matrix consist of: 1. Protein fibers Collagen fibers Elastin fibers Reticular fibers 2. Ground substance (fluid, semifluid, gelatinous, or calcified.).

[Audio] Loose Connective Tissues Areolar connective tissue Adipose tissue Reticular connective tissue.

[Audio] Dense Connective Tissues Contains numerous, thicker, and denser fibers..

[Audio] Cartilage A dense network of collagen fibers and elastic fibers..

[Audio] Bone Tissues 2 types: Compact or spongy..

[Audio] The 3 types of muscle tissue are Cardiac Smooth Skeletal http://www.umm.edu/imagepages/19841.htm.

[Audio] Skeletal Muscle Skeletal muscle fibers occur in muscles which are attached to the skeleton. They are striated in appearance and are under voluntary control. http://www.svcc.edu/departments/Academic/biology/slides/bio110a/skeletal-muscle-longitudinal400x.html.

[Audio] http://www.ucl.ac.uk/~sjjgsca/Muscl eCardiac.html http://webanatomy.net/histology/muscle/muscle_index.htm.

[Audio] Smooth muscle layer of digestive tract: The circular muscle layer runs around the intestine and its contraction causes segmentation. The longitudinal muscle layer runs along the intestine; it causes wave-like contractions. Source: classes.midlandstech.edu.

[Audio] Summary SOURCE: www.stmary.ws. SOURCE: www.stmary.ws Summary.

[Audio] Function: Exhibit sensitivity to various types of stimuli, converts stimuli into impulses (action potentials) and conducts nerve impulses to other neurons, muscle fibers or glands. Consists of two principle types of cells – Neurons or nerve cells. – Neuroglia - supporting cells found in the nervous system. http://explow.com/Nerve_tissue.

[Audio] Neurons exhibit electrical excitability.  The ability to respond to certain stimuli by producing electrical signals such as action potentials.  Actions potentials propagate along a nerve or to cause a response.  Release of neurotransmitters. http://explow.com/Nerve_tissue Source: http://www.uic.edu.

[Audio] Cell body Neuron Axon Prepared by YU KE XIN UEMB4223 NEUROBIOLOGY.

[Audio] Neuroglia Support and bind the component of nervous tissue. Carry on phagocytosis & help supply nutrients to neurons by connecting them to blood vessels. Source: www.lookfordiagnosis.com.

[Audio] Further reading Main text 1. Principles of Anatomy and Physiology, 13th Ed. 2011. Gerard J. Tortora. Wiley. Other references 1. Fundamentals of Anatomy & Physiology 9th Ed. 2012. Frederic H Martini. Pearson/Benjamin Cummings. 2. Human anatomy & physiology 8th ed. 2006, Elaine N. Marieb. Pearson/Benjamin Cummings..