C&T Structure Lecture 1 PDF

Cell and Tissue Structure Introduction Prof Maeve Caldwell Department of Physiology  What is Structure & Function? Integration is key in understanding structure and function you should integrate physiology, anatomy and biochemistry to better understand these modules...

Cell and Tissue Structure Introduction Prof Maeve Caldwell Department of Physiology  What is Structure & Function? Integration is key in understanding structure and function you should integrate physiology, anatomy and biochemistry to better understand these modules 2  Types of Structural Levels Molecular Subcellular Body Tissue Cellular  Organisation of the Body 1. CELLULAR – Basic structural and functional units 2. TISSUE – Collection of specialised cells 3. ORGAN – Made up of a variety of tissues 4. SYSTEMS – Interaction of organs  1. Cellular Levels 1. Epithelium : lining glands, bowel, skin & organs 2. Endothelium : lining blood and lymphatic vessels 3. Mesothelium : lining of pleural, and pericardial spaces 4. Mesenchyme : cells filling spaces between organs, including fat, muscle, bone, cartilage and tendon cells 5. Blood cells : red/white, also those in lymph nodes & spleen 6. Neurons : conducting cells of nervous system 7. Germ cells : reproductive, sperm, oocytes 8. Stem cells : cells able to turn into one or several of above 5  2. Tissue Types 1. Epithelial tissue – Lining/barrier of secretory cells – Skin and mucous membranes 2. Muscle (excitable) tissue – Skeletal (striated) muscle – Smooth muscle – Cardiac muscle 3. Nervous (excitable) tissue – Brain – Spinal cord 4. Connective tissue (cells, fibres, matrix) – Loose connective tissue – Dense fibrous tissue (Capsule, Ligament, Tendon) – Cartilage & Bone – Blood (originate from bone marrow)  3. Organs and 4. Systems ─ MUSCULAR : skeletal muscles, tendons ─ NERVOUS : brain, spinal cord, peripheral nerves ─ C.V.S. : heart, blood vessels, lymphatics ─ SKIN : integmentary ─ IMMUNE : lymphocyte, lymph node, tonsil, spleen ─ RESPIRATORY : nose, pharynx, trachea, bronchi, lungs ─ SKELETAL : bones, cartilage, ligaments ─ G.I.T. : mouth, oesophagus, stomach, intestine ─ SPECIAL SENSES : taste, smell, sight, hearing ─ REPRODUCTIVE : ovary, uterus, testes, epididymus ─ URINARY : kidney, ureter, bladder, urethra ─ ENDOCRINE : pituitary, thyroid, pancreas, adrenals ─ EXOCRINE : tubular, acinar, branched, coiled glands 7 Structure & Function Lect # 1 Epithelial tissue Prof Maeve Caldwell Department of Physiology GLANDULAR SURFACE SPECIAL EXOCRINE ENDOCRINE SENSORY REPRODUCTION PERCEPTION SIMPLE STRATIFIED SQUAMOUS COLUMNAR SQUAMOUS COLUMNAR CUBOIDAL CUBOIDAL The importance of cell biology in medicine How do we get cancer? ? Pathology - Abnormal Cell Biology Changes in cells and tissues: - Size - Number - Shape - Metabolism - Growth - Death  Cellular Diseases NAME Cell effect Notes Atrophy decrease muscle atrophy due to being bed ridden size Hypertrophy increase muscle hypertrophy due to exercise size Hyperplasia increase endometrial hyperplasia due to prolonged oestrogen number exposure Dysplasia change irritation or inflammation due to smoking damages cilia of shape respiratory epithelial cells Metaplasia replace with squamous metaplasia where ciliated respiratory epithelial another replaced by squamous (no cilia) Neoplasia abnormal gene mutation - oncogene (chemical, radiation, viruses), (cancer) growth can be benign and malignant Necrosis death due to injury/disease, where lysosomal enzymes digest cell (autolysis) and inflammation is triggered Apoptosis programmed cells shrink, chromatin fragments, apoptotic bodies death form and phagocytosed by macrophages  Tumours Affected cells are called a neoplasm (tumour) Benign tumours Malignant tumours Primary tumour – original tumour Secondary tumour – at sites distant from primary  Tumours in Majors Tissues TISSUE MALIGNANT BENIGN Epithelia tissue - Epithelia Carcinoma Papilloma - Glandular Epithelia Adeno carcinoma Adenoma Connective tissues - Fibroblast Fibro sarcoma Fibroma - Adipose tissue Lipo sarcoma Lipoma - Blood Leukemia - Lymphoid tissue Lymphoma - Cartilage Chondro sarcoma Chondroma - Bone Osteo sarcoma Osteoma Muscle tissues - Skeletal Rhabdomyo sarcoma Rhabdomyoma - Cardiac Cardiac sarcoma - Smooth Leiomyo sarcoma Leiomyoma Neural tissues - Glia Glioma - Neurons Neuroblastoma  Some Pictures HYPERTROPHY DYSPLASIA HYPERPLASIA LIPOMA OSTEOMA LEIOMYOSARCOMA NECROSIS LIPOSARCOMA OSTEOSARCOMA LEIOMYOMA  Four Tissue Types 1. Epithelial tissue – Lining/barrier of secretory – Skin and mucous membranes 2. Muscle (excitable) tissue – Skeletal (striated) muscle – Smooth muscle – Cardiac muscle 3. Nervous (excitable) tissue – Brain – Spinal cord 4. Connective tissue (cells, fibres, matrix) – Loose connective tissue – Dense fibrous tissue (Capsule, Ligament, Tendon) – Cartilage & Bone – Blood (originate from bone marrow)  What you should know about Epithelia? ─ 1. What are they? ─ 2. What do they do? ─ 3. How are they classified? ─ Simple and stratified ─ Squamous, cuboidal, columnar ─ 4. What do they look like? ─ Cell Membrane Specialisations ─ 5. How do they Proliferate?  I. What are they? ─ Cells close together (minimal matrix between cells) ─ Cell junctions (regulate passage of materials between cells and also provide physical strength) ─ Innervated by nerves (particularly at base) ─ Absence of blood vessels (nutrition is via underlying tissue) 17  II. What do they do? ─ Lining epithelia ─ regulate passage of material in/out of body ─ gut - nutrients ─ lungs - gases ─ kidney - water, ions ─ skin - water ─ Secretory cells ─ secrete body fluids ─ glands ─ ducts  III. How are they classified? GLANDULAR SURFACE SPECIAL EXOCRINE ENDOCRINE SENSORY REPRODUCTION PERCEPTION SIMPLE STRATIFIED SQUAMOUS COLUMNAR SQUAMOUS COLUMNAR CUBOIDAL CUBOIDAL  ‘Glandular’ Epithelia GLANDULAR EXOCRINE ENDOCRINE for secretion see endocrine lecture regulate ion series concentrations 20  Exocrine Glands: Classify by Morphology Simple Types Exocrine glands ─ discharge products via duct ─ simple / compound tubular acinar branched branched coiled large urethra tubular acinar tubular Endocrine glands intestine stomach Mammary sweat ─ secrete hormones gland glands into bloodstream Compound Types 21 tubular acinar Exocrine Glands: Classify by Secretion Merocrine (eccrine) Secretion exocytosis most common type of secretion Apocrine Secretion membrane-bound vesicles example: breasts, sweat glands Holocrine Secretion rupture of secretory cells example: sebaceous glands 22  ‘Surface’ Epithelia SURFACE SIMPLE STRATIFIED SQUAMOUS COLUMNAR SQUAMOUS COLUMNAR CUBOIDAL CUBOIDAL 23  Function of ‘Surface’ Epithelium ─ covers exposed surfaces ─ lines internal passageways and chambers ─ highly cellular ─ avascular ─ capacity to regenerate ─ provide physical protection ─ control permeability ─ provide sensation  Surface Epithelium classification Morphological 1. number of cell layers ─ simple (one layer, permeable) ─ stratified (many layers, protective) ─ 2. shape of cells at free surface ─ squamous (thin, flat, irregular) ─ cuboidal (box-like) ─ columnar (tall, slender, rectangular) 3. surface specialisation (if any) ─ keratin, microvilli, cilia Functional 1. lining types 2. secretion/gland types  8 Types of Surface Epithelium Type Feature Example 3 Simple Types 1. Squamous Diffusion Blood vessels 2. Cuboidal Synthesis of hormones Thyroid gland 3. Columnar Digestion, absorption, Small intestine lubrication 3 Stratified Types 4. Squamous (+/- Protection Skin Keratin) 5. Cuboidal Saliva Salivary gland 6. Columnar Saliva Salivary duct 2 Special Types 7. Pseudostratified Airways Trachea columnar 8. Transitional epithelium Distention Bladder 1. Simple Squamous Example ─ blood vessels 27 2. Simple Cuboidal Characteristics ─ single layer of box-shaped cells ─ locations: ducts and glands Functions ─ synthesis & liberation of hormones collecting tubule Thyroid Gland (kidney) 3. Simple Columnar Characteristics ─ single layer of tall cells Functions ─ digestion (via enzymes) ─ absorption (via microvilli) ─ lubrication (via mucous cells) Small intestine lining of gall bladder With Microvilli - fine extensions of surface membrane — ~1000 per cell 29 4. Stratified Squamous (+/- Keratin) Characteristics ─ many layers (with or without keratin) Functions ─ protection ─ moist surface resists dehydration ─ thermoregulation and sensation uterine Skin Oesophagus cervix (keratinised) non-keratinised keratin ‘flakes’ 30 5. Stratified Cuboidal Example ─ salivary gland 31 6. Stratified Columnar Example ─ salivary gland duct 7. Pseudostratified columnar ciliated Characteristics ─ one layer of cells ─ only tall ones reach surface Functions ─ secrete mucus (goblet cells) ─ trap particles (mucus) ─ move mucus (cilia) ─ clean, warm, moisten (e.g. air) trachea lining of bronchus 33 8. Transitional epithelium Characteristics ─ many layers; all irregularly rounded ─ ureter & bladder only Functions ─ permit distension i.e. increase volume to allow passage of urine lining of bladder IV. Cell Memb. Specialisations of Epithelium Type Functions Basal Surface 1. Basement membrane anchors epithelial cells to underlying tissue Free surface 1. Keratin protective 2. Cilia increase particle movement 3. Microvilli increase surface area for absorption Intercellular junctions 1. Tight junction cell-cell contacts (virtually impermeable to fluid) 2. Adherent junction cell-cell contacts 3. Gap junction permit passage of ions & molecules between cells 4. Desmosome cell-cell contacts 35  Basement Membrane ─ thin, fibrous, non-cellular tissue ─ separates epithelium, mesothelium and endothelium from underlying connective tissue. ─ a matrix that anchors epithelial cells to underlying tissue 36  Surfaces of Epithelium Keratin Cilia Microvilli protective role for movement increase surface area of particles for nutrient exchange skin lining of lining of bronchus small intestine  V. Proliferation in Epithelia Proliferation occurs via Mitosis 1. microtubules form 2. chromosomes duplicate & align at equator (metaphase) 3. chromosomes pull apart 4. cell divides mitoses found in lower part of intestinal Crypts metaphase arrest ─ Vincristine (VCR) prevents formation of microtubules ─ can be injected 3h before removal of tissues proliferation zone  What you should know about Epithelia? ─ 1. What are they? ─ 2. What do they do? ─ 3. How are they classified? ─ Simple and stratified ─ Squamous, cuboidal, columnar ─ 4. What do they look like? ─ Cell Membrane Specialisations ─ 5. How do they Proliferate?