2024_MSPC112_Basic Tissues.pptx

Basic Tissues Nii Koney-Kwaku Koney (NK3) Department of Anatomy [email protected]  How should I study for this course? “The development of the human mind requires structured daily exercises, not a passive and comfortable acceptan...

Basic Tissues Nii Koney-Kwaku Koney (NK3) Department of Anatomy [email protected]  How should I study for this course? “The development of the human mind requires structured daily exercises, not a passive and comfortable acceptance of information.” Copyright © 2007 Dr. Salme Taagepera, All rights reserved. Lecture topic Lecturer/Instructor Definition of Anatomy and its branches, History of Anatomy, Anatomical Dr. Ahenkorah terminology Cell structure and function Dr. Arko-Boham Cell cycle and cell division Dr Blay Gametogenesis, fertilization and early embryonic development (first Prof Addai/Dr Hottor three weeks) Introduction to basic tissues Dr Koney Anatomy of the circulatory system Dr Hottor Anatomy of the respiratory system Dr Koney Anatomy of the musculoskeletal system Dr Ahenkorah Anatomy of the endocrine system Dr Arko-Boham Anatomy of the nervous system Dr Adutwum-Ofosu Date Lecture topic Lecturer 18/05 Definition of Anatomy and its branches, History of Anatomy, Anatomical terminology Dr. Ahenkorah 21/05 Cell structure and function Dr. Arko-Boham 28/05 Cell cycle and cell division Prof Addai/Dr Arko-Boham 04/06 Gametogenesis, fertilization and early embryonic development (first three weeks) Prof Addai/Dr Hottor 11/06 Introduction to basic tissues Dr Koney/Dr Arko-Boham 18/06 Anatomy of the musculoskeletal system Dr Ahenkorah/Dr Adutwum- Ofosu 25/06 Anatomy of the nervous system Dr Adutwum-Ofosu/Dr Ahenkorah 02/07 Anatomy of the circulatory system Dr Hottor/Dr Koney 09/07 Anatomy of the endocrine system Dr Arko-Boham/Dr Koney 16/07 Anatomy of the respiratory system Dr Koney/Dr Hottor 23/07 Anatomy of the digestive system Dr Koney/Dr Arko-Boham Anatomy of the Urinary system Anatomy of the Reproductive system  Books to read Marieb, E. N., & Hoehn, K. (2023). Human Anatomy & Physiology. Pearson. Martini, F., Tallitsch, R. B., & Nath, J. L. (2022). Human anatomy. Vancouver, B.C.: Langara College. McKinley, M. P., O’Loughlin, V. D., & Pennefather-O’Brien, E. (2021). Human anatomy. New York, NY: MHE. Saladin, K. S., & Gan, C. A. (2020). Human anatomy. New York, NY: McGraw- Hill Education. NK3 5  Books to read 1. Gartner, L. P. and Hiatt, J. L., (2013). Colour Atlas and Text of Histology. Lippincott Williams and Wilkins. 2. Mescher, A. (2013). Junqueira's Basic Histology: Text and Atlas, McGraw-Hill Medical. 3. Ross, M. H. and Pawlina, W. (2010). Histology: A Text and Atlas. Lippincott Williams and Wilkins. 4. Sobotta, J. and Hammersen, F. (1980). Histology - A Colour Atlas of Cytology, Histology and Microscopic Anatomy. Baltimore: Urban and Schwarzenberg 5. Wheater, P.R., Young, B., O’Dowd, G. & Woodford, P. (2013). Wheater’s functional histology: a text and colour atlas (with student consults online access). New York, NY: Churchill Livingstone. NK3 6  Histology resources https://www.youtube.com/watch?v=yt3wfHKVCVE https://histology.medicine.umich.edu/resources/epithelia l-tissue https://histology.medicine.umich.edu/resources/connecti ve-tissue https://histology.medicine.umich.edu/resources/muscle https://histologyguide.com//slidebox/slidebox.html https://www.path.uiowa.edu/virtualslidebox/ UofU Slide Viewer (utah.edu) NK3 7 Anything in red is for you to investigate   Objectives By the end of the lecture, you will be able to: Define what tissues are Mention and describe the 4 basic tissues Describe the various functions of the basic tissues  Why tissues? TEAMWORK The human body has trillion of cells However, no one cell can carry out all the necessary bodily functions by itself. So, cells aggregate and form tissues NK3 10  Why tissues? Tissue An organized aggregation of cells, with similar structure that function in a collective manner. Histology Microscopic study of normal tissues NK3 11 The Basic Tissues Four main types of tissues Epithelium Connective Muscle Nerve (Epithelial tissue tissue tissue tissue) Covers body Underlines, Responsible Receives, surfaces supports the for transmits Lines body other three movement and cavity basic integrates Form glands tissues both information structurally to help and control functionally activities of the body NK3 14  Epithelial tissues Where can we find them? Cover exterior body surfaces Eg Line internal closed cavities (including vascular system) and body tubes (alimentary, respiratory and genitourinal tracts) Form glands Secretory portion of glands and their ducts NK3 15 Pancreas Courtesy David  Epithelial tissues General Functions Absorption Columnar epithelium of Intestines and proximal convoluted tubules of kidney Secretion Columnar epithelium of the stomach and the gastric glands Protection Skin NK3 17 Epithelium - Characteristics  Epithelial tissues Characteristics Closely apposed and held together by cell-to-cell adhesion molecules (form junctions), very little intercellular space. They interact with a basement membrane Exhibit polarity They are avascular. How are they nourished? They are capable of regeneration They may have apical modification Cilia, microvilli, stereocilia NK3 19 Epithelial tissues Characteristics Exhibit polarity Free surface or apical domain, lateral domain and basal domain Basal surface is attached to a basement membrane. What is a basement membrane? Epithelium creates a selective barrier between the external environment NK3 and 20 Example Apical No M EC Basal Ep LCT ith eli ries al ce lls LC Capilla T T LC BM Cell Junctions Summary Tight Junctions Adherens Junctions Desmosomes Gap Junctions Hemi- desmosomes What is the difference between desmosomes and hemidesmosomes? NK3 22  Epithelial tissues Classification 1. Number of cell layers Simple 2. Shape of the surface Stratified of the cell Squamous (flat shaped) NB Cuboidal (cube shaped) Specialized type Columnar (pillar shaped) 3. Specialization of apical cell surface Cilia Keratinized or non keratinized Microvilli Stereocilia NK3 23 Epithelial tissues Classification NB Stratified epithelium The shape and height of the cells vary from layer to layer In classifying the epithelium, the shape of the cell at the surface is used. NK3 24 Various types of epithelium NK3 25  Two special categories of epithelium Transitional Epithelium (Urothelium): Specialized to accommodate great degree of stretch and withstand toxicity of urine. Transitional because intermediate between stratified cuboidal and stratified squamous epithelium. In relaxed state appears to be 4-5 cell layers Basal cells: cuboidal or low columnar Intermediate cells: polygonal Surface cells : large round and contain two nuclei the stretched state appears to be 2-3 layers thick NK3 26  Epithelium Pseudo-stratified ciliated columnar epithelium “false” Looks like more than one layer of cells Every cell is anchor to BM GLANDS 28  OBJECTIVES Know the difference between endocrine and exocrine glands Classify glands Know examples 29  Introduction Glands originate from Epithelial cell surface where they developed and penetrate the underlying connective tissue and manufacture a basal lamina around them Parenchyma: Secretory units and the ducts Stroma: Connective tissue that invade and support the parenchyma Varied secretory products Polypeptide hormone (pituitary gland) Waxy substance (ceruminous glands of the ear canal) A mucinogen (goblet cells) Milk (mammary glands) 30 Gland Gland - Types Two types EXOCRINE- release products via ducts ENDOCRINE- secrete into intercellular space from which they enter blood capillaries (ductless)  CLASSIFICATION OF EXOCRINE GLANDS Several criteria are used: Structure of the gland Cell number Shape of secretory portion: Unicellular Tubular in mammals only goblet cells Acinar (alveolar), a small sac-like dilatation Multicellular Stomach lining Duct system Mode of secretion: Simple- single, unbranched duct system Merocrine (eccrine) Compound- branching duct system. Apocrine Sometimes there are a number of groups of Holocrine secretory cells, each group discharging into its Type of secretion own duct. Serous These ducts unite to form larger ducts that Mucous ultimately drain on to an epithelial surface. Seromucous or mixed Such a gland is said to be a compound gland, e.g., parotid gland, pancreas, etc NK3 32  Mode of Secretion: Cells of exocrine gland exhibit different mechanisms for releasing secretions 34  Mode of Secretion: Cells of exocrine gland exhibit different mechanisms for releasing secretions Secretion occurs via Portion of apical Secretory cell exocytosis eg Parotid cytoplasm is released matures, dies and gland with the product e.g. becomes the lactating mammary secretory product. gland Sebaceous gland 35  Type of Secretion Find examples Mucous glands Secrete mucinogen: large glycosylated proteins, Upon hydration mucinogens swell to become a thick viscous gel like protective lubricant called Mucin a major component of Mucus Brunner’s gland, goblet cell Serous glands Secrete enzyme rich fluid Examples: -serous- pancreas, parotid, Paneth cells, chief cells of gastric glands Mixed Produce mucous and serous secretions most salivary glands eg. submandibular NK3 36  Multicellular glands Classification is according to arrangement of the secretory cells and the presence or absence of branching of the duct elements End of the gland is the secretory cell Duct: portion of the gland connecting the secretory cell to the surface of the gland Simple: if their ducts do not branch Compound: branching ducts Secretory units Tubular: secretory portion is shaped like a tube Acinar or Alveolar: secretory portion is shaped like a flask Tubularalveolar: tube ends in saclike dilation NK3 37  Simpe tubular- crypts of Lieberkühn in intestines Simple coiled tubular- sweat gland Simple acinar- penile urethral gland Simple branched tubular- several tubular secretory parts open into one duct- pyloric glands of stomach Simple branched acinar- sebaceous gland Compound tubular- Brunner’s glands in duodenum Compound acinar (alveolar)- pancreas Compound tubulo-acinar (alveolar)- large salivary glands NK3 38 Acinar glands: Glands with secretory unit round or oval in shape, e.g., salivary glands. Alveolar glands: Glands with secretory unit flask-shaped. However, it may be noted that the terms acini and alveoli are often used as if they were synonymous Alveolar (Latin, for hollow sac or cavity) Acinar (Latin, for grape or berry) NK3 40  Read Metaplasia Barrett’s oesophagus Adenoma Adenocarcinoma Kartagener’s syndrome Bullous pemphigoid How are these things related to the epithelium. Find the connection  Connective tissue Composed of living cells and a nonliving material called the extracellular matrix Function Supports organs and cells Act as a medium for exchange of nutrients and wastes between the blood and tissue Protects against microorganism Repairs damaged tissue Stores fat  Connective tissue Cells Fibroblast (Function) Adipose cells Mast cells Macrophages Lymphoid cells Granulocytes  Connective tissue Extracellular content Ground substance Glycosaminoglycans Proteoglycans Glycoproteins Fibers Collagen Reticular Elastic  Connective tissue classification Based on proportion of cells to fibers arrangement and type of fibers  Connective tissue classification Connective tissue proper (they have the characteristics of connective tissue with the fewest deviations from those characteristics) Loose connective tissue Dense connective tissue Embryonic connective tissue Mucous tissue Present in the umbilical cord. Wharton’s jelly Mesenchymal tissue Found in the embryo Other types Elastic tissue Reticular tissue Adipose tissue Specialized connective tissue Cartilage (What are the types of cartilages?) Bone Blood (What are the cells in blood?)  Read Ehlers-Danlos syndrome Marfan syndrome Dupuytren’s disease How are these diseases related to connective tissue? What is sarcoma? What is scleroderma?  Muscle tissue Made up of muscle cells (fibres) that is specialized for contractility and conductivity Possess contractile filaments containing actin and myosin Contraction may be voluntary or involuntary Classified as striated or smooth Skeletal, Cardiac and Smooth  Muscle tissue terminology Muscle cell: Muscle fibres Longer than they are wide Muscle cell membrane: Sarcolemma Cytoplasm: Sarcoplasm Smooth endoplasmic reticulum: Sarcoplasmic reticulum Mitochondria: Sarcosomes  Muscle tissue types Striated or Smooth muscle: presence or absence of regularly repeated arrangement of myofibrillar contractile proteins: myofilaments Striated muscles have alternating light and dark cross bands Striated muscle: Skeletal and Cardiac Smooth muscle  Connective tissue coverings Know these terms Connective tissue coverings Epimysium Perimysium Endomysium Epimysium Dense irregular collagenous connective tissue surrounds entire muscle Perimysium Less dense collagenous tissue surrounds bundles of muscle fibres (fascicle) Endomysium ????????  Differences between the muscles Property Skeletal muscle Cardiac muscle Smooth muscle Shape and size of Long, cylindrical Blunt-ended, Short, spindle shape cell branched Number and location Many, peripheral One, central One central of nuclei Striations Yes Yes No Voluntary Yes No No contractions Intercalated disc No Yes No Distinctive Peripheral nucleus Intercalated disc Lack of striations characteristics Location What is an intercalated disc? What is it’s function?  Identify this structur e A B C Identify these muscles  Nervous System: Function Delivers communication between different parts of the body by specialized nerve cells called neurons Some neurons have receptors for mechanical, chemical and thermal stimuli Transduce these stimuli into nerve impulses that are processed and for perceiving sensations and initiating motor responses  Anatomically, the Nervous System has two major divisions: CNS and PNS What are the components of the CNS? Brain Spinal cord What are the components of the PNS? Cranial nerves Spinal Nerves Autonomic nervous system Enteric nervous  Nerve tissue consist of two cell categories Neuron Responsible for the receptive, integrative and motor functions of the nervous system Do not usually divide. Only their progenitors can. Stem cells differentiate to replace damaged neurons in some areas. Supporting /Neuroglial/Glial Cells Do not receive or transport impulses Can undergo mitosis Physical (protects) and metabolic support of neurons CNS: oligodendrocytes, astrocytes, microglia and ependyma cells PNS: Schwann cells  Functional, Nervous system is divided into two parts Sensory (Afferent component) Receives and transmits impulses to CNS for processing Motor (Efferent component) Originates in the CNS and transmits impulses to effector organs throughout the body  Motor component of PNS is divided into two parts Somatic Nervous system Conscious voluntary control Impulses from CNS to skeletal muscles are directly via a single neuron Autonomic Nervous system Impulses from CNS first are transmitted to an autonomic ganglion via one neuron, a second neuron from autonomic ganglion then transmits impulses to smooth muscles, cardiac muscles and glands Two functional divisions Sympathetic Parasympathetic Neuron Parts of the neuron Cell body (Perikaryon/soma): nucleus, nucleolus, cytoplasm Abundant RER + ribosomes : Nissl bodies Axon Usually one, longest process that carries information away from neuron Extends longer distances from the cell body than dendrite Axon thickness is related to conduction velocity Axon hillock Initial segment Anterograde and Retrograde transport Dendrites shorter processes. Receiving stimuli from sensory cells, axons, other stimuli synaptic junctions Neuron Three categories of neurons based on function Sensory (Afferent) Motor (Efferent) Interneuron communicating network between motor and sensory CNS SAME : This is how I remember Afferent and Efferent!!!!!!! Neurons can be classified based on the number of processes from the cell body Three major categories Multipolar Neurons One axon, two or more dendrites Motor and interneurons Bipolar Neurons One axon, one dendrite Associated with receptors for special senses (taste, hearing, sight, equilibrium). Vestibule and cochlear ganglia, olfactory epithelium of nasal cavity Unipolar Neurons One axon that divides close to the cell body into two long axonal branches One branch to periphery, the other to CNS Dorsal root ganglia Three main types of neuronal forms Neuron Structure Summary Structure Description Neuron/Nerve Structural and functional cell of the nervous cell system Cell body/Soma Nucleus and surrounding cytoplasm Dendrites Processes that conduct information to the cell body Axon Process that conduct information away from the cell body Axon hillock Triangular region connecting axon to cell body Axon collaterals Side branches of axon Telodendria Fine terminal branches of axon  Central Nervous System This is derived from the neural tube Cell bodies of neurons are often grouped together in areas termed nuclei Cell bodies can form more extensive layers or masses of cells termed collectively called grey matter Neuronal dendrite and synaptic activities are mostly confined to areas of grey matter, and they form part of neuronal and glial cell processes which is collectively termed neuropil Axons pass into bundles of nerve fibres called tracts Concentrations of tracts in the cerebral cortices, cerebellum and spinal cord constitute the white matter (axons are usually ensheathed in myelin which is white when fresh) Connective Tissue Investment Bundles of nerve fibers (axon) located outside the CNS and surrounded by several layers of connective tissue Epineurium Perineurium Endoneurium Anything in red is for you to  Glial Cells Supporting /Neuroglial/Glial Cells Do not receive or transport impulses Can undergo mitosis Physical (protects) and metabolic support of neurons CNS: oligodendrocytes, astrocytes, microglia and ependyma cells PNS: Schwann cells  Cell types in the CNS astrocytes, oligodendrocytes, microglia = glia Astrocyte Neuron Capillary Oligodendrocyte Microglia In the PNS: Schwann cells macrophages Astrocytes Most numerous and largest Provide structural and metabolic support Act as scavengers of ions and neurotransmitters released into extracellular space Anchor neurons to capillaries and pia matter Maintains Blood Brain Barrier Recruited to damaged areas of the CNS where they form cellular scar tissue  CNS - Oligodendrocytes capillary myelinated astrocyte Oligodendrocytes axons Electrical insulation and Myelin production One oligodendrocytye may wrap several axons with segments of myelin oligo node dendrocyte Presences of myelin permits the subdivision of the CNS into white and gray matter Schwann Cells myelinated Located in the PNS internodal axons Form myelinated or part unmyelinated covering over axons PNS – Schwann cells Microglia Resident macrophages of the brain and spinal Very small cell cord, and thus act as body, lots of very the first and main fine form of active immune branches,continuo defense in the CNS usly Function as moving! phagocytes in clearing Monitor the debris and damaged health of the structures in CNS neurons Very important because cells of the immune system are denied access in the CNS Unlike other neuroglial cells which are derived embryologically from the neural tube, microglial cells originate from the bone marrow Ependymal cells (Ependymocytes) Low columnar to cuboidal cells Ciliated Line the ventricles of the brain and central canal of spinal cord Modification of some ependymal cells participate in the formation of choroid plexus Secrete and maintains chemical composition of CSF Choroid Plexus Folds of Pia mater Fenestrated capillaries Simple cuboidal cells (ependymal cells) Produce CSF Circulate CSF and Absorbs CSF Divisions of the brain  Read Multiple sclerosis How is it related to the nervous system?  Simple squamous epithelium (Renal corpuscle) LCT BM Apical Basal N  Simple columnar epithelium (Jejunum) Food M (b icr ru ov s h il l bo i BM rd er ) Apical Nucleus LCT Basal  Urinary (transitional) epithelium (Bladder) Urine Dome shaped cells Apical Multiple layers of cells Basal LCT BM  Sole of the foot. Identify: a. type of epithelium b. any specialized feature on the epithelium c. where the basement membrane would be located d. where the connective tissue would be located e. any other structures on this slide that may have an epithelium NK3 81  Oesophagus a. Locate the epithelial region b. What type of epithelium is this? c. How different is it from the sole of the foot? NK3 82  Submandibular gland a. Locate the epithelial region b. What are the two types of epithelium you can see? NK3 83  Transitional Epithelium a. Locate the epithelial region b. Where can you find this type of epithelium? c. Would this be a relaxed or distended state? NK3 84  Medical Application Under certain abnormal conditions, one type of epithelial tissue may undergo transformation into another type. This reversible process is called metaplasia (Gr. metaplasis, transformation). The following examples illustrate this process. In heavy cigarette smokers, the ciliated pseudostratified epithelium lining the bronchi can be transformed into stratified squamous epithelium. This illustrates the great lengths to which the body will go to adapt and protect itself. Find the metaplasia that occurs in the cervical canal of women with chronic infections Read about Barrett’s oesophagus. When the oesophagus is subjected to chronic acid reflux the epithelium changes. What does it change to? Why does it change? In individuals with chronic vitamin A deficiency, epithelial tissues of the type found in the bronchi and urinary bladder are gradually replaced by stratified squamous epithelium. Metaplasia is not restricted to epithelial tissue; it also occurs in connective tissue. NK3 85 The End NK3 86