BIOL 3244: Human Anatomy Notes- Outline
BIOL 3244: Human Anatomy Notes- Outline 3244
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This 24 page Class Notes was uploaded by Alexandra Notetaker on Friday September 2, 2016. The Class Notes belongs to 3244 at University of Colorado Denver taught by Dr. Kent Nofsinger in Fall 2016. Since its upload, it has received 98 views. For similar materials see Human Anatomy in Biology at University of Colorado Denver.
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Body Organization and Anatomic Terminology Anatomy is defined as: (Greek) “to cut up, to dissect”; it is the science concerned with the physical structure of the organism, in this case the human Histology: the study of (normal) tissues Pathology: the study of the disease state and abnormal tissues I. Taxonomic Classification Domain Eukarya Eukaryotic cells o Kingdom Animalia No cell walls, plastids, or photosynthetic pigments Phylum Chordata Dorsal hollow nerve cord, spinal cord Class Mammalia Mammary glands, hair o Order Primates Well developed brain, prehensile hands Family Hominidae Large cerebrum, bipedal locomotion Genus Homo Flattened face, prominent chin and nose, with inferiorly positioned nostrils o Species sapiens Largest cerebrum II. Anatomical characteristics A. Brain weighs: about 1350-1400 grams (~3 lbs) 1. Emotion, thought, reasoning, memory, precise, coordinated movement B. Bipedal locomotion C. Sigmoid curvature of the spine, anatomy of hips and thighs, arched feet D. Opposable thumb –true of all primates E. Well-developed vocal structures, have articulated speech F. Stereoscopic vision: gives us depth perception III.Levels of organization of the human body A. Cellular Level: basic structural and functional component of life. We have 60-100 trillion cells. Organelles – carry out a specific function within the cell. B. Tissue Level: an aggregation of similar cells that perform a common function. Four principal kinds of tissues: 1.Epithelial : covers body surfaces, lines body cavities, and forms glands and ducts 2.Connective tissues : bind, support, and protect body parts; includes the blood a) Matrix: nonliving intercellular material (liquid, semisolid, solid) secreted by tissue cells 3.Muscle tissue : contracts to produce movement 4.Nervous Tissue : initiates and transmits nerve impulses from one body part to another C. Organ Level: an aggregate of tissue types that perform a specific function. Usually there is a primary tissue and secondary tissue. However, an organ will have all four tissues. D. System Level: a body system consists of various organs that have similar or related functions. Examples – circulatory, respiratory, digestive, nervous, endocrine. The systems of the body are interrelated and make up the organism IV. Anatomy is a new language. Learning anatomy will be very much like learning another language. We need a starting point. A. All anatomical terms are in relationship to what is known as the anatomical position. 1. The body is erect, the feet parallel, the eyes directed forward, the arms to the sides, and the palms directed forward, with the fingers straight down. 2. It is imperative to learn this position, and remember that all anatomical terms come from this position. V. Terms A. Positions 1. Superior: directional reference meaning above 2. Inferior: directional reference meaning below 3. Anterior: pertaining to the front of the body 4. Posterior: pertaining to the back of the body 5. Ventral: towards the chest or belly 6. Dorsal: towards the back 7. Medial: toward the midline of the body 8. Lateral: away from the midline of the body 9. Proximal: toward the trunk of the body 10. Distal: away from the trunk of the body a) Frequently, in the digestive system, proximal means closer to the mouth and distal is closer to the anus b) Sometimes in the circulatory system, proximal means closer to the arterial side, and distal will mean closer to the venous side 11. Ipsilateral: on the same side 12. Contralateral: on the opposite side 13. Rostral (lit.: “towards the beak”) in neuroanatomy, towards the forehead 14. Caudal: in neuroanatomy, away from the forehead, towards the spinal cord B. Movement 1. Flexion: movement that decreases the angle of the parts of the joint 2. Extension: movement that increases the angle of the parts of the joint 3. Hyperextension: extension of the joint past anatomic position- the neck, shoulder, hip 4. Adduction: movement towards the axis or midline of the body 5. Abduction: movement away from the midline of the body 6. Supine/supination: placement of a body part so that the anterior surface is superior 7. Pronate/pronation: placement of a body part so that the posterior surface is superior 8. Circumduction: the distal end of the body part describes a circle, but the bone does not rotate C. Special movements 1. Inversion: a turning inward, as the ankle 2. Eversion: a turning outward, as the ankle 3. Dorsiflexion: with the ankle, the superior surface of the foot approaches the shin 4. Plantar flexion: with the ankle extension of the foot – pointing the toes 5. Retraction: A body part moves posteriorly in a horizontal plane 6. Protraction: A body part moves anteriorly in horizontal plane 7. Elevation: moves a body part superiorly 8. Depression: moves a body part inferiorly 9. Lateral flexion: moves the vertebral column in a lateral direction (to the side) VI. Body Regions There are other ways of describing locations within the human body. Anatomists will talk about regions and quadrants of the abdominopelvic regions as well as the cavities located in the body. In addition, things can be described with respect to various imaginary planes that bisect the body. A. Major Regions of the Body – see text for more complete list 1.Cephalic: head 9.Inguinal: the groin 2.Cervical: neck 10.Lumbar: lower back 3.Thoracic: chest 11.Gluteus: buttocks 4.Brachium: the arm from the shoulder 12.Femur: thigh to the elbow 13.Patella: kneecap 5.Antebrachium: the forearm 14.Crus: the leg from the knee to 6.Antecubital: the front of the the ankle elbow 15.Talus: the ankle 7.Carpus: wrist 16.Plantar: sole of foot 8.Pubis: the anterior pelvis B. Abdominal quadrant system – frequently used clinically; marked by a mid-sagittal and transverse plane through the umbilicus 1.Left upper quadrant 2.Right upper quadrant 3.Left lower quadrant 4.Right lower quadrant C. Abdominal subdivision System 1.Left and Right Hypochondriac regions – a) Left and right upper one-third regions of abdomen 2.Left and Right Lumbar (or Lateral) Regions a) Left and right middle lateral regions of abdomen 3.Left and Right Iliac (or inguinal) regions a) Left and right lower one-third regions of abdomen 4.Epigastric Region a) Upper, central one third of abdomen 5.Umbilical region a) Center of abdomen 6.Hypogastric a) Lower, central one-third of abdomen VII. Body Planes A. Sagittal and Midsagittal Planes: 1.Sagittal plane: a vertical plane that divides the body into left and right portions 2.Midsagittal plane: the plane that passes through the mid-plane of the body, dividing it equally into right and left halves (plane that goes through middle of body) B. Transverse or horizontal: Divide the body into superior and inferior portions C. Frontal or coronal: A vertical plane that divides the body into anterior and posterior portions VIII. Body Cavities A. Dorsal Body cavity 1. Cranial cavity: contains the brain 2. Vertebral cavity: contains the spinal cord B. Ventral Body Cavity: divided by diaphragm 1. Thoracic cavity: upper or chest cavity a) Pleural: two pleural cavities surround the right and left lungs b) Mediastinum: the area between the two lungs c) Pericardial: the cavity that surrounds the heart 2. Abdominopelvic Cavity: lower ventral cavity a) Abdomen: upper contains stomach, small intestine, liver, gall bladder, pancreas, and spleen b) Pelvis: contains the terminal portion of the large intestine, the urinary bladder, certain reproductive organs IX. Body Membranes A. Mucous membranes (noun – mucus): Produce thick, sticky fluid. Line various cavities and tubes that enter or exit the body: oral, nasal cavities, respiratory, reproductive, digestive systems. B. Serous Membranes – Line the ventral body cavity: line the thoracic and abdominopelvic cavities and cover visceral organs, producing a watery lubricant called serous fluid or a transudate. *serous membranes DO NOT produce serous fluids 1. There are two layers: a) Parietal – the outermost layer, surrounds the cavity b) Visceral – the innermost layer, surrounds the organ(s) 2. The subdivisions a) Visceral/parietal pleura; pleural cavity (line lungs) b) Visceral/parietal pericardium; pericardial cavity (line heart) c) Visceral /parietal peritoneum; peritoneal cavity (line abdomen) Greater and lesser omentum: folds of peritoneum that extend from the stomach; for protection this perineum is visceral peritoneum; lesser omentum suspends the peritoneum and the greater omentum continues from the lesser omentum; omentum is connective tissue and includes adipose tissue Mesenteries: double folds of peritoneum that connect the parietal peritoneum with the visceral peritoneum.; Mesenteries wrap around bowel; mesenteries hold bowel so it doesn’t drop and sit on the bladder and other body parts; this peritoneum is parietal peritoneum C. Synovial membranes – produce synovial fluid – fluid within certain joints 1. Composed entirely of connective tissue – the exception to the rule that body cavities are lined by epithelium D. Cutaneous membrane – the skin X. Intercellular junctions: found on lateral sides of epithelial cells A. Zonula occludens or tight junctions: protein molecules in adjacent cell membranes fuse together like a zipper, forming an impermeable barrier, which keeps molecules from passing between cells; e.g., the digestive tract 1. Don’t confuse with zonula adherens: an anchoring junction which bind to the cytoskeletons of adjacent cells B. Desmosomes: Anchoring junctions, mechanical couplings like rivets scattered along the sides of adjacent cells. More significant than adhesive belt junctions. Found in tissues under mechanical stress, like the heart, skin, uterus. C. Gap junctions: allows chemical to pass between adjacent cells. Gap junctions exist in electrically excitable tissues like the heart and smooth muscle, where passage of ions from one cell to another helps to synchronize the cells together. Vocabulary (be able to define, use, or give examples of) Anatomy Extension Brachium Parietal Cell Adduction Antebrachium Visceral Tissue Abduction Antecubital Peritoneum Organ Inversion Carpus Pleura Organ system Eversion Pubis Pericardium Superior Dorsiflexion Inguinal Perineum Inferior: Plantar flexion Lumbar Umbilicus Anterior Supination Gluteus Mediastinum Posterior Pronation Femur Epi- Ventral Circumduction Patella Hypo- Dorsal Retraction Crus Gastro- Medial Protraction Talus Osteo- Lateral: Elevation Plantar Chondro- Proximal Depression Hypochondriac Hyper- Distal: Lateral flexion Iliac Peri- Ipsilateral Cephalic Epigastric Histology Contralateral Cervical Umbilical Pathology Flexion Thoracic Hypogastric Matrix Introduction to Epithelial Tissues I General D. Epithelium covers and lines: 1. The skin 2. The coverings of the cardiovascular, digestive, respiratory, urinary, and reproductive system. It covers the walls and organs of the ventral body cavity Names/types a) Epithelium: (outer); skin, mucous membranes b) Mesothelium: (middle); covers visceral organs and lines body cavities c) Endothelium: (inner); lines inner walls of blood and lymphatic vessels E. Glandular: epithelium makes up the majority of the glands of the body 1. Exocrine glands: secretions pass through ducts 2. Endocrine glands: ductless glands that secrete hormones directly into the blood or lymphatic fluid Functions: -Protect -Absorb -Filter -Excrete/Secrete -Sensory reception (its in your ears, nose, eyes, parts of skin and works with nervous tissues to facilitate nerve action) XI. Characteristics of Epithelium Covering and lining epithelia can be classified by a number of different morphologic characteristics. These include the presence of a basement membrane, the number of cell layers of the tissue, and the shape of the cell A. Cellularity: composed of closely packed cells, with little extracellular material (or matrix) B. Polarity: have an apical surface (exposed to external environment) and basal surface (exposed to internal environment – next to a basement membrane) Apical specializations a) Microvilli: fingerlike extensions of the cell that increases the ability to absorb or secrete – kidney tubules, intestinal tract b) Cilia: propel substances along their free surface, like the trachea C. Attachment: Basement membrane: underlying supportive material 1. Basal lamina: a thin, supportive sheet of non-cellular glycoproteins that lies adjacent to the basal surface of the epithelium 2. Reticular lamina: deep to the basal lamina and is a network of collagen protein fibers that are part of the underlying connective tissue D. Innervated – have nerve fibers E. Avascular – have no blood vessels F. Regenerate rapidly XII. Specific Types of Epithelium A. Classification Based in part on number of cell layers 1. Simple: a single cell layer (1) Since it is thin, it is concerned with absorption, secretion, and filtration, but not protection. Located in: kidney tubules 2. Stratified: consists of 2 or more cell layers stacked on each other (1) Found where protection is important. (2) They regenerate from the basal layer and push apically as they mature (from bottom to the top) 3. Pseudostratified Simple: the cells are only a single layer thick, but the cells vary in height and have nuclei located at different levels from the basement membrane, giving the appearance that it is several layers thick. Will not contain distinct layers. Located: Respiratory epithelium which has cilia, also found in male urethra Based in part on cell shape a) Squamous: flattened laterally with sparse cytoplasm. The close fitting, scale-like cells resemble a tiled floor. b) Columnar: are tall and column shaped c) Cuboidal: are boxlike, about as tall as wide B. Simple epithelia – every cell touches the basement membrane 1. Simple squamous epithelia: found where filtration or exchange is a priority, e.g. the filtration capsules of the kidneys, air sacs in the lungs a) Endothelium lines the lymphatic vessels as well as the cardiovascular system. b) Mesothelium is the epithelium found in serous membranes lining the ventral body cavity 2. Simple cuboidal epithelia: are found where secretion and absorption are important: located in glands, kidney tubules 3. Simple columnar epithelia: are found where absorption and secretion are important: lines the stomach and intestinal tract 4. Pseudostratified columnar epithelia: secrete or absorb substances; found along most of the respiratory tract C. Stratified epithelia 1. Stratified squamous epithelia a) Several layers of cells that become progressively flattened as they mature apically b) Forms the epidermis; the outer layer of the skin, where it is keratinized, that is the surface contains keratin, a tough protein. It is also found in the mouth, tongue, pharynx, esophagus, rectum and vagina. 2. Stratified cuboidal a) Uncommon, found in larger ducts of some glands: mammary, sweat, and salivary glands 3. Stratified columnar epithelia: a) Uncommon, found in male urethra 4. Transitional epithelia: a) Cells of its basal layer are cuboidal or columnar, while the apical cells vary in appearance from rounded to flattened depending on the distention of the organ; urinary bladder D. Epithelium- Review 1. Simple a) Squamous—lines vascular and lymphatic sacs (alveoli), filtration to kidneys b) Cuboidal—kidney tubules, glandular epithelium c) Columnar—stomach, small and large intestine lining d) Pseudostratified—lines the trachea and bronchi 2. Stratified e) Squamous—skin, mouth and esophagus, vagina f) Cuboidal—uncommon; ducts of mammary, sweat and salivary gland g) Columnar—uncommon; male urethra h) Transitional—urinary bladder, ureters, urethra XIII. Glandular Epithelia As with membranous epithelia, glandular epithelia can be characterized depending on several morphologic characteristics as well. These include number of cells, branching patterns, shape, and secretion. A. Number of cells 1. Unicellular: single celled glands, like goblet cells found in the epithelial linings of the respiratory and digestive tracts. 2. Multicellular: composed of both secretory and cells that form the walls of the ducts. B. Branching Patterns 1. Simple: ducts do not branch (only 1 generation of ducts) 2. Compound: branching ducts C. Gland shape 1. Tubular: the gland resembles a tube or test tube in chem. 2. Alveolar or acinar: the gland resembles a flask D. Secretion Types 1. Mucoid gland: secrete glycoproteins (a larger protein attached to a carbohydrate) called mucin that absorb water to form a slippery mucus 2. Serous gland: secrete a watery solution that usually contains enzymes, such as the enzyme amylase found in saliva 3. Mixed exocrine glands contain more than one type of gland cell and may produce two different exocrine secretions, one serous and one mucous. The submandibular gland is an example. E. Mechanisms of Release of Secretion 1. Merocrine secretion: secretory vesicles are discharged – goblet cells 2. Apocrine secretion: some of the cytoplasm of the cell becomes the secretory product – milk production by the lactiferous glands. Fat droplets coalesce in the cytosol, which then buds with a thin coating of cytosol and the plasma membrane. 3. Holocrine secretion: the entire cell becomes packed with secretory products, and the cell disintegrates as the secretion is released – sebaceous hair glands 9 Introduction to Connective Tissues I Functions F. Establish a structural framework for the body G. Transport fluids and dissolved materials from one region of the body to another H. Provide protection for delicate organs I. Supporting, surrounding, and interconnecting other tissue types J. Storing energy reserves, especially as lipids K. Defending the body from invasion by microorganisms XIV. Characteristics A. CT is the most abundant tissues in the body, but are never exposed to the environment outside the body B. CT includes fat, bone, cartilage, and blood – tissues quite varied in appearance and function C. Most CT have multiple functions, but no single tissue performs all of these functions D. Basic components: 1.Specialized cells 2.Extracellular protein fibers 3.A fluid known as the ground substance – the matrix that surrounds cells a) Most of the volume of CT is matrix XV. General Histology of Connective Tissue A. Fibers 1.Collagenous fibers – contain collagen which is flexible but with tremendous strength. It is long, straight and un-branched. Each fiber contains 3 fibrous protein subunits that are wound together like a rope. a) Tendons are almost entirely collagen, and connect muscle to bone b) Ligaments resemble tendons, but connect one bone to another. c) The parallel alignment of collagen fibers allows them to withstand tremendous forces. 2.Reticular fibers – form a delicate latticework or reticulum by branching. Common in lymphatic glands, liver, spleen 3.Elastic fibers – contain elastin, which is thinner, wavy, branching, and more elastic than collagen. Found in intervertebral ligaments a) After stretching up to 150% of their original length, they can recoil to their original length B. Intercellular matrices or ground substances 1.Ground substance is usually clear, colorless, and has a consistency similar to maple syrup. 2.It contains a glycosaminoglycan (a protein polysaccharide): hyaluronan. A glycoaminoglycan contains polymers of amino sugars connected to protein. C. Cells 1.General Types a) –blasts: immature or active cells b) –cytes: mature or cells in a quiescent state 10 c) –clasts: cells that remodel or break down connective tissue, such as osteoclasts in bone 2. Specific types a) Fibroblasts: most abundant fixed cell in connective tissue proper. Elongate or stellate (star-shaped) are responsible for production and maintenance of CT fibers. Each fibroblast manufactures and secretes protein subunits that interact to form large extracellular fibers. In addition, secrete hyaluronan. b) Macrophages: are large amoeboid cells that are scattered among the fibers. They engulf and destroy damaged cells or pathogens that enter the tissue. When stimulated, they release chemicals that initiate the inflammatory response, and attract large numbers of wandering cells. c) White blood cells d) Adipocytes: fat cells or adipose cells. A typical cell contains a single enormous lipid droplet, squeezing the nucleus and other organelles to one side of the plasma membrane. The number of fat cells will vary from region to region and individual to individual e) Mast cells: are small CT cells often clustered around blood vessels. They have secretory histamine granules. Also produce heparin, an anticoagulant that prevents blood from clotting within blood vessels. f) Mesenchymal cells are stem cells that can produce daughter cells that are fibroblasts, macrophages, or other CT cells. Can be any type of connective tissue (blood, bone, cartilage, CT proper) g) Tissue specific: osteocytes (bone), chondrocytes (cartilage) D. Classification of Connective Tissue 1. Types a) Connective tissue proper: contains CT cells, extracellular protein fibers (collagen, reticular or elastic fibers), and an abundant ground substance (matrix) b) Supporting connective tissue: cartilage and bone are the 2 types c) Fluid connective tissue: blood and lymph are the 2 types Connective Tissue Classification Common origin: mesenchyme C.T. Proper Supporting C.T. Fluid C.T. 11 Blood Loose CT Dense CT Cartilage Bone Lymph (fewer fibers, (more fibers, (semisolid (solid matrix) more ground less ground matrix) substance substance XVI. CAdiposeve TissueRegular Hyaline Compact A. Loose Connective Tissue: much of the space is occupied by ground substance 1.Adipose Tissue:rregular Fibrocartilage a) Fat is not only an energy source, but supports and protects, as well as insulates. b) Concentrated around the kidneys, in the hypodermis of the skin, surface of the heart, surrounding joints, under side of groin, buttocks, around eyes, and in breasts of sexually mature females. c) For the most part are formed prenatally and during the first year of life. d) Adipocytes are incapable of dividing, but mesenchymal cells can differentiate into additional adipocytes. Adipocytes are not killed by weight reduction. 2.Reticular: a) Characterized by a network of reticular fibers woven through a jelly-like ground substance. b) Contains fibroblasts and macrophages; the latter are phagocytic and ingest foreign materials or deteriorating cells (like RBC’s in the spleen). c) Liver, spleen, lymph nodes, and bone marrow contain reticular CT. 3.Areolar: a) Least specialized of CT b) Separates skin from deeper structures—hypodermic c) Open framework, with ground substance accounting for most of the volume d) Cushions, shocks, and can be distorted without damage, and with elastic fibers it is resilient, returning to its normal shape when pressure is relieved. e) Fibers – collagen fibers predominate with some elastic and reticular fibers Mast cells are also present. f) Cells: fibroblasts predominate. g) Intercellular matrices: major feature of the Connective Tissue Proper. Also called interstitial fluid; when it accumulates, as in inflammation or disease, called edema. B. Dense or Collagenous 1. Regular (Dense Regular Connective Tissue): large amounts of densely packed, parallel collagen fibers that run parallel to the direction of force placed on the tissue. Silvery white in appearance, and sometimes called white fibrous CT. a) Tendons – muscles to bones, and transfer force of contraction b) Ligaments – connect bone to bone across articulations (joints) c) Aponeurosis: collagen sheets or ribbons that resemble broad flat tendons 2.Elastic Connective (Yellow Elastic) Tissue: (1) Composed primarily of elastic fibers, most fibers run parallel, but there is branching, and have yellow color. (2) Found in the walls of large arteries, portions of the trachea and bronchial tubes, and underlies transitional epithelium 12 3. Irregular (Dense Irregular Connective Tissue): large amounts of densely packed, interwoven collagen fibers that provide tensile strength in any direction. Found in dermis of skin, submucosa of the gastrointestinal tract, and fibrous capsules of joints and organs. XVII. Supporting Connective Tissues A. Cartilage: Consists of cartilage cells or chondrocytes in a firm gel that contains complex polysaccharides called chondroitin sulfates associated with proteins. Chondrocytes are the only cells within cartilage, and live in little pockets known as lacunae. Collagen fibers provide the tensile strength. Cartilage produces a chemical that discourages blood vessel formation, and it is avascular. 1. Cartilage grows in 2 ways: a) Appositional – the perichondrium adds additional chondroblasts to the outside edges of the cartilage to widen it. Allows cartilage to grow wider b) Interstitial growth – chondrocytes within the cartilage divide and secrete new matrix – this thickens the cartilage in the middle c) Cartilage stops growing in the late teens 2. Types of cartilage a) Hyaline: most common. Closely packed but very fine collagen fibers; it is somewhat flexible, so it is the weakest. Examples in the adult: connections between ribs and sternum, supporting cartilage along respiratory tract, covering articular surfaces of long bones within synovial joints like the elbow or knee. b) Fibrocartilage: the matrix is reinforced by numerous interwoven, collagen fibers. Found between vertebrae, and in the menisci of the knees. Much stronger. c) Elastic cartilage: similar to hyaline, except that it has abundant elastic fibers that make it very flexible without compromising its strength. This tissue is found in the outer ear, portions of the larynx, and in the auditory canal. B. Bone 1. Most rigid of all CT. 2. Has a rich vascular (blood) supply and is active metabolically. 3. About 1/3 of matrix is cartilage-- collagen fibers – contributes to flexibility 4. Rest of matrix is due to calcium salts – mostly calcium phosphate and calcium carbonate – contributes hardness 5. Bone compares favorably to best steel-reinforced concrete on a weight basis Approximate tensile strength of bone and other materials Material Tons/Inch Cast Iron 5-10 Copper 10 BONE 10 Wood 7 Tendon 7 13 XVIII. Fluid Connective Tissue A. Blood: 1.Cells or formed elements suspended in a liquid matrix called plasma. 2.Cells include erythrocytes-red blood cells, leukocytes-white blood cells, and platelets a) Leukocytes: white blood cells b) Erythrocytes: red blood cells c)Platelets – cellular fragments that assist in blood clotting B. Lymph 1.Matrix is interstitial fluid – mainly fluid that has left the vascular system and needs to be returned to it 2.Cells are mainly lymphocytes – a type of WBC Vocabulary (be able to define, use, or give examples of) Histology Apical Mesenchyme Chondrocytes Cytology Serous Fibroblast Regular fibers Basement membrane Mucoid Fascia Irregular fibers Matrix Apocrine Collagen Loose connective tissue Epithelium Merocrine Reticular Dense regular and Stratified Holocrine Elastic fibers irregular connective Simple (tissue) Acinar (alveolar) Erythrocytes tissue Pseudostratified Microvilli Leukocytes Elastic connective tissue Squamous Simple glands Macrophages Hyaline cartilage Transitional epithelium Compound glands Mast cells Fibrocartilage Mesothelium -blast Tendons Elastic cartilage Endothelium -cyte Ligaments Cilia -clast Adipose 14 Integumentary System This will be the first system we will discuss this semester, and it will be a discussion of the largest organ in the body as well, the skin. There are numerous part to this system that include: Skin, Hair, Nails, Glands I General Features of Skin Determines initial impression: consider the time devoted to acne commercials on TV compared to blood pressure medication Mirrors general health of other body systems Largest organ of the body – accounting for ~7% body weight It covers about 21 sq. feet in the average adult Averages 1.5 mm thick, depending on location, varying from 6 mm on palms and soles to 0.5mm on tympanic membrane. Coordinates immune response to pathogens and cancers in skin C. Embryology 1.The 2 week embryo: a) Develops the epidermis from the outer layer of the ectoderm b) Develops the dermis from the mesoderm D. Layers of Integument 1.Epidermis and dermis—2 layers of skin 2.Some references include the hypodermis XIX. Functions of the Skin A. Protection 1.Physical barrier—to microorganisms, water, excessive UV light 2.Oily secretions – form an acidic film that retards growth of microorganisms, and makes the skin water-resistant B. Temperature Regulation 1.Normal body temperature is maintained by: a) Radiant heat loss from dilated blood vessels b) Evaporation or perspiration – sweat about 100-150 ml/day for every 1-degree increase in body temp. c)Retention of heat from constricted blood vessels: arrectores pilorum, smooth muscle attached to hair follicles contract and cause goose bumps C. Excretion 1.Excretes water, electrolytes, drugs, and urea D. Synthesis 1.Small amounts of UV light are necessary for the synthesis of Vitamin D – whi3h helps to regulate calcium and phosphorus metabolism E.Sensory Reception 1.Cutaneous receptors- sensory nerve cells that respond to heat, cold, pressure, touch, vibration; monitor changes in temp., not actual/absolute temp. 2.Vary in distribution- some on hands, face, etc. F. Communication 1.Emotions are expressed in skin color 2.Contraction of facial muscles express a variety of emotions 15 3. Secretions from integumentary glands have odors which may stimulate subconscious responds from others XX. Epidermis A. General Features 1. Most superficial protective layer 2. Varies in thickness from 0.007-0.12 mm thick 3. Only the deepest layers are living cells 4. The palms and soles have 5 layers, the rest of the body has 4 layers B. The Five Layers of the Epidermis – deep to superficial 1. Stratum Basale (stratum germinativum) a) A single layer of cells along the dermis b) Attached to the basal lamina c)4 cell types (1) Keratinocytes – specialized keratin-producing cells. Keratin toughens and waterproofs the skin. As the cells are pushed superficially the nuclei degenerate, and the keratin completely dominates the cell. Purpose—to form a strong cytoskeleton, form intracellular bonds and as the cell dies, the keratin is left in place (a)These are the ONLY cells found apical (superficial) to the stratum spinosum (2) Melanocytes – synthesize the pigment melanin, which provides a protective barrier to UV radiation for the basal cells. Melanin is transferred from melanocytes to keratinocytes. In light- skinned people, some of the melanin is digested by lysosomes above the basal layer. (a)Expressions of melanocytic variations (i) Tanning - Gradual exposure to UV results in increased production of melanin within melanocytes (ii) Racial variation - Individual and racial differences in skin color result from different levels of melanocyte activity, not different numbers of melanocytes. (iii) Albinism - Even albinos have normal numbers of melanocytes. Albinism is due to inability to convert tyrosine to melanin (iv) Freckles – aggregations patches of melanin (v) Vitiligo – localized whitening of skin due to lack of melanocytes (vi) Seborrheic keratosis – “liver spots”: after ~50, brown, plaque-like growths on exposed skin (3) Tactile (Merkel) cells – sensory cells aiding in touch reception; light touch perception- superficial; attached to neurons (4) Langerhans cells – protective macrophages which are mobile and patrol the skin for microorganisms that are looking for wayward bacteria 2. Stratum Spinosum (“spiny layer”) a) Each time a stem cell in the stratum basale divides, a daughter cell is pushed into the next layer, where it begins to differentiate into a keratinocyte b) Several layers thick c)Keratinocytes are bound together by desmosomes (1) Shrinkage of the cells during fixation, which are bound together by desmosomes, give layer its scallop appearance d) Cell division can continue in this layer – therefore the stratum basale and stratum spinosum are collectively called the stratum germinativum e) Friction at the surface results in additional mitotic activity resulting in a callus 3. Stratum Granulosum a) Cells are now manufacturing large amounts of keratohyalin and keratin 16 b)The cells become flatter and thinner, and cell membranes become thicker c)The nuclei and other organelles disintegrate 4.Stratum Lucidum a)Present only in soles and palms b)Appears glassy, and doesn’t stain well with standard stains 5.Stratum Corneum a)Consists of 15-30 layers of flattened, dead, interlocking cells b)Connections from the stratum spinosum remain intact, adding strength c)Cell are usually shed in large groups or sheets, rather than individually d)Containing large amounts of keratin, it is keratinized or cornified (1) Occurs everywhere except on anterior surface of eyes e)Relatively dry, therefore unsuitable for many microorganisms f)Water resistant, but not waterproof, and we lose about 500 ml (~1 pt) of water a day through the skin g)It takes about 14 days for a cell to move from the stratum basale to the stratum corneum, and about another 14 days before the cells are shed Stratum basale Stratum germinativum – older terminology Stratum spinosum Stratum granulosum Stratum lucidum – only in palms and soles Stratum corneum XXI. The Dermis A. General Features 1. Deep to epidermis, and much thicker 2. Integumentary effectors: muscles or glands that respond to motor impulses from the nervous system 3. Vascular supply – helps regulate body temperature and BP 4. Lines of tension – elastic and collagen fibers are arranged in patterns. a) Decreasing elastic fibers is associated with aging b)Vascular – to support epidermis c) Contains many sweat glands, oil-secreting glands, nerve endings, and hair follicles B. Layers 1. Papillary layer a) Areolar CT b)Superficial layer in contact with the epidermis c) Numerous projections – papillae – extend from the dermis into the epidermis 2. Reticular layer (stratum reticularosum) 17 a) Dense irregular CT, that surrounds blood vessels, hair follicles, nerves, and glands b)Deeper and thicker than the papillary layer c) Can be “torn” during pregnancy or obese individuals (1) Repair leaves a white mark called a linea albicans XXII. Hypodermis or subcutaneous tissue A. Characteristics 1. Not part of the skin, but binds the dermis to underlying organs 2. Composed of areolar CT, adipose, and blood vessels 3. Females typically have an 8% thicker hypodermis than males 4. Stores lipids, insulates, and cushions, regulates temperature 5. Subcutaneous fat is stored a) Men – neck, upper arms, along lower back, over buttocks b)Women – breasts, buttocks, hips, and thighs XXIII. Glands of the integument We spent some time earlier talking about the various types of glands in the body based on cell structure, branching patterns, and secretion patterns. In the skin we can talk about three very specific types of glands, sudoriferous glands, sebaceous glands, and ceruminous glands A. Sudoriferous glands (sweat glands)– can be broken down into two subcategories 1. For evaporative cooling and secretion of wastes 2. Eccrine (or Merocrine) – widely distributed over skin, especially forehead, back, palms, and soles. Function in evaporative cooling 3. Apocrine – are much larger. Found in axillary and pubic regions, and secrete into hair follicles. May act as a sexual attractant; don’t function until puberty. Apocrine secretions of mature women have been shown to alter the menstrual timing of other women. a) Mammary glands – specialized sudoriferous glands that secrete milk during lactation B. Sebaceous glands 1. Oil glands that secrete sebum onto shaft of hair root 2. Commonly associated with hair follicles 3. Lubricates and waterproofs stratum corneum 4. Holocrine glands 5. Regulated by sex hormones, and hyperactivity can result in acne C. Ceruminous glands 1. Found only in external auditory canal (ear canal) 2. Secrete cerumen or earwax 3. Water and insect repellant 4. Keeps tympanic membrane (ear drum) flexible XXIV. FYI A. Skin cancer: 1. Melanoma a) Arises from melanocytes in skin. b) Ultraviolet radiation causes epidermal cells to mutate and become cancerous. 2. Squamous cell 18 a) Arise from epidermal cells in skin b) Associated with sites of skin damage: including UV light exposure 3. Basal cell a) Accounts for 75% of skin cancers b) Resemble the normal basal layer of the epidermis c) Usually associated with skin damage from UV light B. UV light also contributes to age related cataracts, and macular degeneration 1. People who spent more than 5 hours a day in the sun as youths were more likely to develop macular degeneration when older Vocabulary Integument Stratum spinosum Albinism Epidermis Stratum granulosum Vitiligo Dermis Stratum lucidum Sudoriferous Hypodermis (subcutaneous) Stratum corneum Sebaceous Stratum basale or stratum Keratinocytes Ceruminous germinativum Merkel cells 19 20 The Axial and Appendicular Skeleton • The human skeleton is divided into two different divisions –Axial Skeleton: the skull, bones of the thorax, and the vertebral column, including the sacrum and coccyx –Appendicular Skeleton: the extremities and their supporting elements-- the shoulder and pelvis girdle. * You will be covering the gross anatomy of both of these divisions in the lab. In lecture, we will be covering the histology and general anatomy of compact bone. I Functions of the Skeletal System At birth the skeleton consists of about 270 bones, which decreases to about 206 bones by adulthood. Bone fusion occurs C. Support 1. Rigid structure to which softer tissues and organs are attached 2. The skeleton can support a weight of up to 5 times the weight of the bones themselves D. Protection 1. The skull protects the brain 2. The vertebral column the spinal cord 3. The rib cage, the heart, lungs, liver, and spleen 4. The pelvic girdle cradles the digestive and reproductive organs E. Hematopoiesis (Hemopoiesis) 1. RBC”S, WBC’s, and platelets are produced from stem cells within the red marrow. An average of 2.5 million RBC’s are produced every second F. Storage 1. The calcium salts of the bone act as a reservoir for valuable minerals like calcium and phosphate. a) 95% of calcium is stored in the bones and teeth b) Calcium is the most abundant mineral in the body; it is necessary for blood clotting, movement of ions across cell membranes, and muscle contraction G. 90% of phosphorus is stored in the skeleton; it is necessary for the activities of the nucleic acids. 1. Magnesium, sodium, fluorine, and heavy metals like strontium are stored in bone tissue 2. Fat stored in the yellow marrow acts as an energy reserve XXV. Types of bone A. Long bones 1. Longer than they are wide 2. Function as levers 3. Most of the bones of the upper and lower extremities: a) Humerus c) Ulna b) Radius d) Metacarpal bones 21 e) Femur g) Metatarsal bones f)Tibia h) Phalanges B. Short bones 1. Somewhat cube-shaped 2. Found in wrist and ankle 3. Transfer forces of movement C. Flat bones 1. Broad surface for muscle attachment or protection of underlying organs a) Cranial bones 1. Additional bones that develop in tendons in response to stress b) Ribs c) Bones of shoulder girdle across a joint a) Patella D. Irregular bones 1. Varied shapes F. Accessory bones 1. Bones that are supernumerary 2. Many surface attachments for or not usually present muscles or articulation a) Bones of skull, face, vertebrae 2. Usually short or flat and occur in hands and feet E. Sesamoid bones G. Sutural bones 1. Extra bones within the sutures of the skull 22 H.