Histology Unit 3
Most multicellular organisms have some way to transport substances across distances which are too far for diffusion, which system is the best for this task.
Circulatory system
Epiphysial plate
Epiphysial plate showing endochondral ossification calcified cartilage is converted to bone by the action of osteoclasts and osteoblasts
Capillaries
Fenestrated (visceral) • Contain small openings in membrane • Each fenestrae closed by diaphragm • Basal lamina is continuous
Number 54: Identify the tissue layer be specific
Perichondrium
Number 43: Is this relaxed or expanded lung tissue?
Relaxed lung tissue
Endochondral Ossification
• Occurs in hyaline cartilage template • Forms long and short bones • 2 Phases - Hypertrophy and destruction of chondrocytes - Osteogenic bud of osteoprogenitor cells invades spaces left by chondrocytes • Long bones form epiphysis at each end and diaphysis in between • Cartilage calcifies during early stages of bone formation; calcified cartilage is basophilic (blue) and new bone is acidophilic (pink) • Primary ossification begins in diaphysis • Later secondary ossification centers form at each epiphysis • As epiphyseal plate growth continues, matrix produced is processed into bone by expanding diaphyseal ossification center
Hyaline Cartilage Chondrocytes
• Outer ones elliptical with long axis parallel to surface • Deeper ones round, may be in groups of up to 8 - isogenous group (from mitotic divisions of a single cell) • Lined up in rows in epiphyseal plate • Often shrunken in histological sections
Components of Blood
• Plasma • Formed elements (Blood cells) - Erythrocytes (red blood cells) - Leukocytes (white blood cells) - Platelets
Thrombopoiesis
• Platelets come from the megakaryocyte line of development in the bone marrow • Stages of development - Megakaryoblast - Promegakaryocyte - Megakaryocyte with platelets • Invaginations of the plasma membrane of the megakaryocyte form demarcation membranes • Demarcation membranes define the areas of cytoplasm that are shed from the megakaryocyte as platelets
Alveoli Interesting facts
• Pores (10-15 m) in interalveolar septa allow for equalization of air between alveoli and air circulation when a bronchiole is obstructed • Cells - Capillary endothelial cells (thin walled) - Type I squamous epithelial cells • 97% of the alveolar surface • Very thin (sometimes 25 nm thick) • Organelles grouped around nucleus • Attached by desmosomes (prevents leaking of fluids)
Erythrocytes
• Produced in the bone marrow • Circulate for about 120 days (1-3 days as a reticulocyte before completely mature) • Most are removed in the spleen • Biconcave in shape; • 6-8 m in diameter • No nucleus • Contain hemoglobin for carrying oxygen and carbon dioxide • Perform their functions inside the blood vessels • Stain pink with Wright/Giemsa stain Normally erythrocytes are very flexible Cell membrane contains about 40% lipid, 50% protein and 10% CHO
Functions of the Respiratory System
• Provides large area for gas exchange • Moves air to and from the lungs • Protects respiratory surfaces from variations such as dehydration, etc. • Defends against foreign invaders • Produces sounds and assist with smell • Assists in regulation of blood volume and pH
Respiratory Epithelium
• Pseudostratified, ciliated columnar epithelium with numerous goblet cells • Lines nasal cavity and pharynx • Conditions the inhaled air :Filters, warms, humidifies air.
Remodeling and Growth of Bone
• Resorption of bone matrix and deposition of new bone remain active throughout life • As bone matrix is added to outer bone surfaces marrow cavity enlarges leading to increase in bone diameter • Bone length increases due to epiphyseal plate growth • Bone diameter increases as periosteal cells differentiate into new osteoblasts and deposit new bone on the surface
Terminal Bronchiole
• Respiratory bronchioles - Arise from terminal bronchioles - Lined by ciliated cuboidal epithelium and Clara cells - As bronchioles get smaller • Ciliated cuboidal epithelium loses cilia and eventually are continuous with simple squamous epithelium of alveoli • Walls are interrupted with sac-like alveoli - Lamina propria contains smooth muscle and elastic fibers - No cartilage or glands
Closure of the Epiphyseal Plate: 5 Zones of Epiphyseal Cartilage
• Resting zone: hyaline cartilage • Proliferative zone: rapidly dividing chondrocytes form columns of stacked cells • Hypertrophied cartilaginous zone: large chondrocytes with glycogen in cytoplasm • Calcified cartilage zone: chondrocytes dying, deposition of hydroxy apatite in matrix • Ossification zone: endochondral bone appears, vessels invade from periosteum, matrix calcifies
Alveoli
• Sac-like invaginations about 200 m in diameter located on respiratory bronchioles, alveolar ducts and alveolar sacs • Sites of exchange of O2 and CO2 between blood and air • Alveoli are separated by interalveolar septa - 2 thin simple squamous epithelial layers between capillaries (richest capillary network in the body), elastic and reticular fibers, and connective tissue matrix and cells (leukocytes, macrophages, fibroblasts)
Characteristics of Bone
• Same components found in all connective tissue : cells, fiber, and matrix. • Contains nerves • Metabolically very active (vascularized) • Surrounded externally by periosteum and internally by endosteum
Perichondrium
• Sheath of dense irregular connective tissue and vasculature surrounding cartilage • Articular cartilage lacks perichondrium, nutrients from synovial fluid
Capillaries
• Single layer of endothelial cells; 1-3 cells • 7- 9 m in diameter; < 50 m long • 60,000 miles of capillaries in human body • Endothelial cells rest on basal lamina • Pericytes enclose the endothelial cells - May have contractile function (contain actin, myosin, tropomyosin proteins) - Can proliferate and differentiate to form new blood vessels and connective tissue cells following injury to vessel • Zona occludens present between cells
Intramembranous ossification
• Source of most flattened bones such as skull, mandible and maxilla • Starts with mesenchyme tissue • Primary ossification centers form when cells differentiate into osteoblasts • Islands of developing bone are spicules • Fusion of spicules forms spongy bone • Form around in growing vessels • In skull, internal and external plates of compact bone are separated by layer of spongy bone
Basic Components of Connective Tissue
• Specialized cells - Chondroblasts divide to produce new cartilage - Chondrocytes synthesize and secrete extracellular matrix to ; reside in lacunae • Extracellular protein fibers - Mostly collagen - May contain elastin • Ground substance (fluid)
Bone
• Specialized connective tissue of: - calcified bone matrix - 3 cell types • osteocytes in lacunae • osteoblasts make new matrix and maintain old matrix • osteoclasts: multinucleated giant cells phagocytose bone matrix in remodeling bone • Viewed as ground bone sections or decalcified and embedded paraffin sections • Endosteum and periosteum Osteoprogenitor (stem) cells
Functions of Bone
• Supports fleshy structures such as muscle • Important in posture and movements • Protects vital organs • Produces and stores developing blood cells in bone marrow • Reservoir for ions, such as calcium, phosphate and others • Important in transfer of vibrations: hearing
Osteoblast
• Synthesize and maintain matrix (collagen, proteoglycans, and glycoproteins) • Part of endosteum, simple cuboidal • Become osteocyte when surrounded by matrix • Osteoid = newly made uncalcified matrix
Bone Matrix
• Synthesized and maintained by osteoblasts and osteocytes • 50% is inorganic: calcium and phosphate • Hydroxy apatite crystals • Organic part is 95% type I collagen with amorphous ground substance (glycosaminoglycans, glycoproteins)
Leukocytes
• Total number in peripheral blood is 4,500 - 11,000 /µL • Mostly produced in bone marrow; leave blood by diapedesis to function in tissues (see page244, Fig. 12-6) • Function in cellular and humoral defenses against foreign invaders; attracted by chemotactic factors • Classified based on the type of granules in the cytoplasm and the shape of their nucleus - Granulocytes (polymorphonuclear) - Agranulocytes (mononuclear)
Functions of Blood
• Transportation of dissolved gases • Distribution of nutrients • Transportation of metabolic wastes • Delivery of enzymes and hormones • Stabilization of pH and electrolyte composition of interstitial fluid • Prevention of fluid loss • Defense against toxins and pathogens • Stabilization of body temperature
Structural Plan of Arteries
• Tunica intima - Single endothelial layer - Subendothelial loose connective tissue with occasional smooth muscle cell - Internal elastic lamina (membrane) of elastin • Contains gaps that allow diffusion of substances to nourish deeper cells • Tunica media - Concentric rings of smooth muscle - Varying amounts of elastic and reticular fibers - Ground substance (proteoglycans and glycoproteins) - Smooth muscle cells produce extracellular matrix - External elastic lamina (in some vessels) • Tunica adventitia - Collagen fibers (type I) - Elastic fibers - Continuous with connective tissue layer of organ - Vaso vasorum
Monocyte
• Usually about 12-20 µm in diameter • Largest circulating blood cell • Nucleus is oval, horse-shoe or kidney shaped; lighter staining than lymphocytes • Cytoplasm is gray or light bluish; sometimes contains a few small azurophilic granules (lysosomes) •Probably differentiate into macrophages when they enter the tissues • Increased in blood in tuberculosis
Lymphocyte
• Vary in size from small (6-8 µm in diameter) to medium and large sizes (up to 18 µm in diameter) • Nucleus is mononuclear (no segments) • Cytoplasm is usually dark blue to gray and may contain a very few azurophilic granules • May live for days or even years • Only WBC to return to blood after leaving tissues • Functionally have T, B and natural killer cells • Increased in blood in infectious mononucleosis
Blood Supply to Blood Vessels
• Vasa vasorum - Arterioles, capillaries and venules that branch in the tunica adventitia and outer part of the tunica media - Furnish nutrients to these areas of the blood vessel - More frequent in veins than arteries
Bone Marrow
• Yellow - adipose tissue • Red - Stroma • Meshwork of reticular cells and fibers • Contains collagen types I and III, fibronectin, laminin, proteoglycans, hemonectin - Hematopoietic cords of developing blood cells - Sinusoids
Chondrocytes
•Appear withdrawn in lacunae but artifactual; living chrondrocytes fill up complete lacunae •Synthesize collagen and other matrix molecules •Depend on nutrients from blood vessels in perichondrium •Normal function depends on balance of hormones •Growth dependent on somatotropin (GH) from pituitary
The endosteum is formed of which of the following tissues?
loose irregular connective tissue
The presence of both afferent and efferent lymphatic vessels is only associated with which of the following structures or organs?
lymph nodes
Number 12: what cell is this?
lymphocyte
Number 51: Identify :
lymphocytes
All of the following statements concerning red blood cells are true EXCEPT (which statement is the false statement)
mature erythrocytes demonstrate a large area Golgi area
Platelets are derived from which of the following cells?
megakaryocytes
Which of the following structures is a component of the 'conducting zone' of the respiratory tract?
nasopharynx secondary bronchus larynx
Megan thinks that she has an abscessed tooth. If she does, what type of white blood cell would you expect to see increased in a white blood cell count?
neutrophil
Number 11: what cell is this?
neutrophil
Which of the following blood cells is identified as a granular leukocytes?
neutrophil
Which of the following fiber types is secreted by an osteocyte?
none of the above
A well-developed Golgi apparatus is most characteristic of which of the following cells associated with bone tissue formation?
osteoblast
Identify the marked cell
osteoblast
Identify the marked bone cell
osteoclast
Which of the following bone cells is not related by cell lineage to other bone cells?
osteoclast
Which of the following cells is not a component of the 'endosteum'?
osteocytes
Which of the following cells is not mitotic (incapable of mitosis)
osteocytes
Which of the following cells has the primary role of giving raise to daughter cells (capable of mitosis)
osteogenic cells (osteoprogenitor cells)
All of the following are covered with the endosteum a when viewing tissue for typical long bone EXCEPT.
outer circumferential lamellae
Which of the following layers of bone matrix is found just deep to the periosteum?
outer circumferential lamellae
Identify the cell marked by the arrow.
plasma cell
The 'red pulp' of the spleen contains large numbers of
platelets
Which one of the following forms the feathery molecules which entrap water molecules in the cartilage matrix?
proteoglycans and glycosaminoglycans
Number 52: Identify :
pseudostratified columnar with cilia
Number 14: what cell is this?
red blood cells
Number 45: Identify this tissue by name?
red blood cells
Agranular leukocytes are formed (derived from stem cells) in which of the following organs or regions?
red bone marrow
Lymph nodes perform all of the following functions EXCEPT
removal of excess nutrients from lymphatic fluid
Number 39: identify the region by name, be specific.
respiratory bronchiole
Alveoli are present in which of the following airways?
respiratory bronchioles alveolar ducts
Number 47: Identify
respiratory membrance
Which of the following epithlia is found lining the secondary and tertiary bronchi?
simple columnar epithelium
Which of the following epithlia is found lining the bronchioles of the lung?
simple cuboidal epithelium
Number 55: Identify the tissue layer and organ be specific
smooth muscle arteriole
Number 40: identify the region by name, be specific.
terminal bronchiole
Given the area identified by the letter D is?
territorial matrix
Lymphocytes are found in all of the following organs EXCEPT
the brain
Which of the following components of a typical long bone is covered by "periosteum"?
the diaphysis
The body's lymphocytes are produced and stored in all of the following EXCEPT
the kidneys
Most of the lymphatic fluid returns to the cardiovascular circulation by way of the
thoracic duct
Which of the following structures is found in the 'anterior mediastinum' of the thoracic cavity
thymus
Number 17: layer is this ?
tunica externa 18 is tunica interna
In the general structural plan of the blood vessel wall, which layer contains concentric rings of smooth muscle and the external elastic lamina?
tunica media
Which of the following types of bone cells would be located in the endosteum lining the osteon (central) canal or covering trabecular bone spicules?
two answers are correct
The epicardium of the heart is also known as the
visceral serous pericardium
Osteoblasts are found in all of the following locations EXCEPT
within the epiphyseal growth plate (zone of proliferating cartilage)
Basophil
• About same size as neutrophils • Nucleus is sometimes difficult to see because of granulation that appears to cover it • Contains large, bluish/purplish staining granules (metachromatic) that are filled with histamine and heparin • Very similar to mast cells in morphology and components but arise from different stem cells in the bone marrow • Increased in blood in hypersensitivity disorders
Eosinophil
• About the same size as neutrophils • Usually bilobed with two lobes connected by a thin strand of chromatin • Contains many large refractile specific granules that stain with eosin (red) • Granules contains peroxidase and major basic protein (See table 12-2 in text) • Elevated in the blood in parasitic infections and allergies/hay fever
Neutrophils
• Active phagocytes; important defense against infection • Lysozyme breaks down bacterial cell wall • Half-life 6-7 hrs in circulation; lifespan 1-4 days in tissue • Normally around 12-15 µm in diameter • Contains a nucleus with 2-5 segments connected by thin strands of chromatin • Contain 2 types of granules - See table 12-1, pg. 239 in text • Very active phagocytic cells • Elevated in the blood in infections • Human females may have inactivated second X chromosome (drumstick)
Lymphopoiesis
• All lymphocytes originate in bone marrow • Many circulating lymphocytes arise in the lymphoid organs such as the spleen, lymph nodes and tonsils • Stages of development - Lymphoblast - Prolymphocyte - Lymphocyte (T and B cells)
Alveolar sacs/ducts
• Alveolar duct and alveolar sacs - Open into atria with alveolar sacs - Lumen lined by simple squamous epithelium - Smooth muscle in lamina propria eventually disappears - Elastic fibers and reticular fibers form wall of alveolar duct and alveolar sacs after smooth muscle disappears - No cartilage or glands
Hyaline Cartilage Matrix
• Amorphous ground substance with proteoglycans such as chondroitin sulfate and keratin sulfate • Territorial matrix adjacent to chondrocytes has much glycosaminoglycan and stains darker than non-territorial matrix
Platelets
• Arise from megakaryocytes in the bone marrow • 2-4 µm in diameter • Non-nucleated; cytoplasmic fragments • Function in many ways including platelet aggregation to form platelet plug and clot retraction; also participate in blood coagulation with platelet factor 3 • Morphological regions visible on LM - Hyalomere - Granulomere • Ultrastructure of platelets - Peripheral zone • Open canalicular system • Dense tubular system - Cytoskeleton zone • Microfilaments and microtubules - Organelle zone • Mitochondria; glycogen • Dense bodies - calcium, ADP, ATP • Alpha granules - fibrinogen, platelet-derived growth factor
Elastic Cartilage
• Auricle of ear, external auditory canal, eustachian tube, epiglottis, cuneiform cartilage of larynx • Similar to HC, but an abundant amount of elastic fibers • Perichondrium
Hematopoiesis
• Blood first arises from yolk sac mesoderm • Primitive blood cells migrate to the liver and spleen, which then become sites of hematopoiesis • Before birth, bone marrow takes over as the primary site of blood production • All cell types are produced in the bone marrow • Lymphocytes are also produced in lymphoid organs
Alveoli Membrane
• Blood-air barrier - Total thickness 0.1 to 1.5 m - Composition • Simple squamous epithelial cell of alveoli • Basal lamina of the epithelial cell • Basal lamina of the endothelial cell • Endothelial cell of the blood capillary - Both basal laminae fuse to form the basement membrane
Hyaline Cartilage
• Blue-white in color • In embryo it serves as skeleton until replacement by bone, acts as template • Epiphyseal plate in long bone growth • Joint surfaces (articulate cartilage) , nose, larynx, trachea, bronchi, ends of ribs adjacent to sternum • Extracellular matrix (con't) - Mostly type II collagen fibrils (small) - Hydrated gel of proteoglycans and hyaluronic acid - Structural glycoproteins • Chondronectin - Binds to glycosaminoglycans and type II collagen - Responsible for mediating the adherence of the chondrocyte in the matrix
Nerves of the respiratory system
• Both parasympathetic and sympathetic nerves innervate the smooth muscle in the respiratory system • Sensory nerves carry poorly localized pain sensations from the lungs • Most nerves travel in connective tissue around larger airways
Bronchial Tree
• Bronchi - 2 primary bronchi (1 left and 1 right) branch from trachea; supply left or right lung - 5 secondary bronchi (2 left and 3 right) branch from primary bronchi; supply lobes of lungs (2 to 3 per lung) - 8-10 tertiary bronchi; supply bronchiopulmonary segments of lungs (8-10 per lung) • Bronchi (con't) - Lumen lined by RE - Lamina propria • Smooth muscle (spirally arranged); increases as bronchi get smaller in diameter • Elastic fibers • Mucous and serous glands • Lymphatic nodules (BALT) - Hyaline cartilages change from C-shaped rings to plates as bronchi get smaller in diameter
Pulmonary Blood Vessels
• Bronchial arteries and veins supply the bronchial tree to the respiratory bronchioles • Pulmonary arteries and veins exchange air with the blood and alveoli - Pulmonary arteries leave the heart and carry deoxygenated blood to the alveoli; travel with bronchial tree - Pulmonary veins carry oxygenated blood from the alveoli to the heart for circulation; travel in interlobular septum
Joints
• Classification of Joints - Synarthroses (little or no movement) • Synostosis - between skull bones (sutures) • Synchrondosis - cartilage fills in the space between bones (epiphyseal plates, costal cartilages) • Sydesmosis - dense connective tissue fills in the space between bones (between radius and ulna) - Diarthroses (freely moveable)
Periosteum
• Collagen bundles and fibroblasts layer on outer bone surface (superficial layer) • Vasculature • Osteoprogenitor (stem) cells can form new osteoblasts (deep layer)
Features of Cartilage
• Connective tissue with very firm extracellular matrix • Avascular; the vasculature in adjacent perichondrium • Diffusion of oxygen and nutrients via the perichondrium or synovial fluid • Chondrocytes have low metabolic activity • No innervation (nerve supply) • No lymphatic vessels (fluid drainage)
Pharynx
• Connects nasal cavity with larynx and esophagus • Lumen lined by different types of epithelium based on location • Lamina propria (connective tissue) lies deep to epithelium • Skeletal muscular supports walls of pharynx • Divisions - Nasopharynx - between the internal nares and the soft palate; lined by Respiratory Epithelium = pseudostratified ciliated columnar epithelium. - Oropharynx - between the soft palate and the base of the tongue at the hyoid bone; lined by non-keratinized stratified squamous epithelium - Laryngopharynx - between the hyoid bone and the esophagus; lined by non-keratinized stratified squamous epithelium
Trachea
• Connects the larynx and primary bronchi • Lumen lined by RE • Seromucous glands located in lamina propria • 16-20 C-shaped hyaline cartilage rings in lamina propria connective tissue provide support • Open end of cartilage ring lies posterior and is bridged by ligament and trachealis muscle (smooth muscle)
Larynx
• Connects the pharynx with trachea • Rigid wall of hyaline Cartilage • Lumen lined by different types of epithelium in different regions • Lamina propria lies deep to epithelium • Walls supported by 9 cartilage plates - Unpaired: thyroid, cricoid, epiglottis - Paired: arytenoid, corniculate, cuneiform
Tissue Components of the Vascular Wall
• Endothelium - Simple squamous epithelium • Smooth muscle - In all vessels except capillaries and pericytic venules (postcapillary venules) • Connective tissue - Collagen fibers - Elastic fibers - Ground substance
Wright Stain Components
• Eosin • Methylene blue or any oxidative products • Methyl alcohol • Phosphate buffer, pH 6.4 - 6.7
Epiglottis Epithelial coverings
• Epithelial coverings - Epiglottis - lingual and apical surface of laryngeal surface covered by non-keratinized stratified squamous - Remainder of laryngeal surface covered by RE • Mucosal folds - False vocal cord (vestibular fold) - covered by RE - True vocal cord (vocal fold) - covered by non-keratinized stratified squamous; vocalis skeletal muscle regulates tension on ligament - Muscle tissue is also present
Functions of Cartilage
• Facilitates bone movements • Supports soft tissues (nose, ear, trachea) • Shock absorption, pulling forces, and friction reduction in joints without permanent distortion • Development and growth of most bones • Chondrocytes are located in lacunae and maintain the extracellular matrix • Matrix: hyaluronic acid, proteoglycans, glycoproteins and fibers.
Primary Bone: First Generation
• First to be formed • Replaced by secondary except near sutures, in flat bones of skull, tooth sockets and insertion areas of some tendons • Decreased mineral content and more osteocytes per unit volume than secondary bone
Hyaline Cartilage Perichondrium
• Found around all HC except joint HC • Dense irregular connective tissue necessary for growth and maintenance of cartilage • Contains many undifferentiated mesenchyme cell that may differentiate into new chondrocytes
Types of Leukocytes in Peripheral Blood
• Granulocytes - Neutrophil segmented: 50-70% - Eosinophils: 0-4% - Basophils: 0-2% • Agranulocytes - Lymphocytes: 20-44% - Monocytes: 2-9%
Venules
• Have a few smooth muscle cells in their walls • Usually travel with arterioles • Have thinner wall and collapsed lumen when compared to arterioles
Forms of Cartilage
• Hyaline: most common, type 2 collagen • Elastic: elastic fibers, type 2 collagen • Fibrocartilage: dense network of type 1 collagen; high stress and weight bearing
Developmental Bone Tissue: 2 Types
• Immature, primary or woven bone where collagen bundles have random orientation • Mature, secondary or lamellar bone where collagen bundles are oriented in bone lamellae often organized in Haversian systems
Large Elastic Arteries
• Include aorta and its large branches • Yellowish in color due to elastic fibers • Tunica intima - Thickest of all vessels - Hard to differentiate internal elastic lamina from other layers • Tunic media - Contains 40-70 layers of elastic laminae - Also contains smooth muscle cells, reticular fibers and ground substance • Tunica adventitia is small in amount
Medium Muscular Arteries
• Include arteries such as the brachial, radial, ulnar, femoral, etc. • Tunica intima - Thicker subendothelial layer than arterioles - Prominent internal elastic lamina • Tunic media - Contains up to 40 layers of smooth muscle - Also contains elastic and reticular fibers and ground substance - External elastic lamina only in larger arteries • Tunica adventitia - Contains vaso vasorum, lymphatics and nerves
Cartilage Growth
• Interstitial growth: mitotic division of existing chondrocytes and production of matrix • Appositional growth: differentiation of new chondrocytes from stem cells and production of matrix at surface
Fibrocartilage
• Intervetebral disks, tendon and ligament attachment to bone, pubic symphysis • Combination of HC and dense regular connective tissue • Usually merges with adjacent dense connective tissue • Chondrocytes often in rows or groups • Matrix acidophilic due to high collagen • No perichondrium
2 Types of Bone Histogenesis
• Intramembranous ossification: occurs in a layer of condensed mesenchyme • Endochondral ossification: occurs within a cartilaginous template; cartilage precursor is gradually replaced by ossified tissue differentiating from the surrounding periosteum
Osteoclasts
• Large, multinucleated, and motile cells • Phagocytes of endosteum • Fused monocytes • Acidophilic cytoplasm, many lysosomes, many mitochondria • Secrete acid, collagenase and other proteases that break down the matrix - Parathyroid hormone in blood causes osteoblasts to stimulate increased osteoclast activity (increased Ca++ in blood); calcitonin decreases activity of osteoclasts (decreased Ca++ in blood)
Small Arteries and Arterioles
• Less than 0.5 - 1.0 mm in diameter • Tunica intima - Small subendothelial layer - Internal elastic lamina present in small arteries - Internal elastic lamina absent in arterioles • Tunica media - Contains one or two circular arranged smooth muscle cells in arterioles and a few more smooth muscle cells in small arteries - No external elastic lamina • Tunica adventitia - Very thin
Endosteum
• Lines all internal bone surfaces (marrow cavities) • Osteoblasts, osteoclasts, and osteoprogenitor cells, small amount of connective tissue
Osteocyte: long lived
• Located in lacunae (sing. lacuna) • Filopodia in canaliculi connect to other osteocytes via gap junctions - route for nutrient movement; few vessels • Maintain surrounding matrix - Contain fewer RER and reduced Golgi than osteoblasts • Death of osteocytes will lead to bone resorption (long lived)
Pulmonary Lymphatic Vessels
• Lymph vessels follow bronchial tree and the interlobular septum • All drain into lymph nodes in the region of the hilum • Lymphatic vessels not found below the terminal branches of the bronchial tree or alveolar ducts
Lymphatic Vascular System
• Lymphatic capillaries - Thin walled vessels; closed-ended - Collect fluid from tissues and returns it to blood - Transports lymph fluid and lymphocytes - Composed of single layer of endothelium and incomplete basal lamina - Have some elastic fibers in walls
Macrovasculature vs Microvasculature
• Macrovasculature - Vessels are more than 0.1 mm in diameter - Includes muscular and elastic arteries, large arterioles, muscular veins • Microvasculature - Visible only with a microscope - Includes small arterioles, capillaries and postcapillary venules - Site of exchanges between blood and tissues
Secondary Bone
• Made up of osteons - Complex of concentric lamellae - around a canal containing vessels, nerve and loose connective tissue - Lacunae found between and within lamellae • Osteon have long, often branched canals connected to marrow cavity and periosteum • Osteon interconnect via transverse Volkmann's canals (no surrounding lamellae)
Monopoiesis
• Monocytes are produced in the bone marrow • Enter blood and circulate about 8 hours • Leave blood to enter tissues to become macrophages where they function for several months • Stages of development - Monoblast - Promonocyte - Monocyte
Innervation of Blood Vessels
• Most blood vessels are supplied by unmyelinated sympathetic nerve fibers • Transmitter diffuses from the adventitia to smooth muscle cells in the tunica media
Respiratory Epithelium (RE)
• Most of the conducting portion of the respiratory system is lined by ciliated pseudostratified epithelium • 5 cell types of respiratory epithelium - Ciliated columnar cells • Most abundant cell type • 300 cilia per cell - Goblet cell • Next most abundant cell type • Produce mucous
Components of the Respiratory System
• Nose (vestibule and nasal cavity) • Pharynx (nasopharynx, oropharynx, laryngopharynx) • Larynx • Trachea • Bronchi - Primary bronchus - Secondary bronchus - Tertiary bronchus • Bronchiole • Terminal bronchiole • Respiratory bronchiole • Alveolar duct • Alveolus
Mechanisms of Calcification
• Not completely understood • Alkaline phosphatase causes accumulation of phosphate for precipitation of hydroxy apatite crystals • Calcium binding glycoproteins secreted • Vesicles in osteoblasts accumulate calcium and phosphate for calcification
Which of the following structures is a component of the 'conducting zone' of the respiratory tract?
Two answers are correct
Alveoli Type II cells
Type II cells • 3% of alveolar surface • Round cells that contain lamellar bodies (1-2 m), which give the cytoplasm a foamy appearance • Lamellar bodies contain surfactant (protein-lipid substance) • Surfactant coats the Type I alveolar cell surface that surrounds the lumen of alveolus • Surfactant reduces surface tension - Needed to inflate alveoli (at birth) - Prevent collapsing of alveoli during expiration - Lack of surfactant causes respiratory distress syndrome
Alveoli Support cells
- Alveolar macrophages (dust cells) - Located in the interalveolar septum and on the surface of the alveolus • No cartilage or glands
Cell types of respiratory epithelium
- Brush cell • Columnar cell that contains microvilli on its apical surface • Contains afferent nerve endings on basal surface - Basal (short) cell located on basal lamina; do not extend to surface; generative stem cell for other cells - Granule cell contains numerous 100-300 nm granules with dense cores; neuroendocrine cell
Small or medium-sized Muscular Veins
- Diameter ranges from 1-9 mm - Tunica intima • Endothelium • Thin subendothelial layer (may be absent) - Tunica media • Small bundles of smooth muscle cells • Reticular and elastic fibers - Tunica adventitia • Collagen fibers • Well-developed
Heart Wall: Endocardium
- Endocardium • Similar to tunica intima • Endothelium (simple squamous) • Thin layer of subendothelium with loose connective tissue of elastic and collagen fibers and some smooth muscle cells - Subendocardial layer of veins, nerves and Purkinje cells connects endocardium to myocardium
Heart Wall epicardium
- Epicardium • Simple squamous epithelium (mesothelium) • Also contains thin layer of connective tissue (with veins, nerves, ganglia, adipose cells) • Forms the visceral layer of the pericardial sac
Lymphatic vessels
- Larger than lymphatic capillaries - Eventually empty into thoracic duct or right lymphatic duct (ducts empty into veins near heart) - Have walls similar to veins except thinner with no defined tunics - Contain many valves
Heart Wall: Myocardium
- Myocardium • Thick layers of cardiac muscle - cells oriented in many directions • Muscle layers insert into fibrous skeleton
Smell (olfaction)
- Specialized pseudostratified columnar epithelium • Supporting cells with microvilli • Basal cells at base of epithelium • Olfactory cells - Bipolar neurons with 6-8 apical cilia that are adapted as receptors; basal portions of cells continue as axons toward olfactory bulb - Bowman's glands in lamina propria of underlying connective tissue clears cilia
Large veins Muscular Veins
- Tunica intima • Well-developed • May contain valves • (2 layers of endothelium supported by elastic connective tissue fibers) - Tunica media • Few layers of smooth muscle cells • Abundant connective tissue - Tunica adventitia • Thickest tunic • May have some longitudinal bundles of smooth muscle
Which of the following is the approximate normal hematocrit value for men?
40 - 50%
The cells of the tissue below is know for secreting large amounts of ?
B and D black and white pic
Histogenesis of Cartilage
Cartilage does not regenerate well (by perichondrium) and may be replaced by scar tissue
Capillaries Types
Continuous (somatic) • Have no fenestrae in wall • Found in all types of muscle tissue, connective tissue, exocrine glands and nervous tissue
The 'trachealis' muscle
is formed of smooth muscle cells oriented to pass in the longitudinal orientation along the trachea
Cardiac muscle
is similar to skeletal muscle in that it is striated
Which of the following is the most numerous leukocyte found in infected tissue?
NOT neutrophil
Which of the following is not the function of one or more white blood cells?
NOT transport oxygen
Which of the following structures or regions is lined by stratified squamous epithelium?
laryngopharynx
Which of the following types of cartilage is found in the growth plates of bone, between the ribs and the sternum, and the nose? Correct!
hyaline cartilage
Long Bone
ie humerus
Destruction of red bone marrow by radiation (as in preparation for a bone marrow transplant) would result in which of the following?
infections such as mononucleosis due to the loss of lymphocytes
Which of the following layers of bone matrix is found just encircling the medullary cavity?
inner circumferential lamellae
The tissue below is would be found?
intervertebral disc
Which is a component of the respiratory portion of the respiratory system? Correct!
alveolar duct
Which of the following structures is a component of the 'respiratory zone' of the respiratory tract?
alveolar duct alveolus terminal bronchiole
Which of the following vessels has the largest amount of elastic tissue in its tunica media?
aorta
From your readying of the textbook, cartilage growth which occurs just deep to the perichondrium from the division of chondroblasts is identified as . . .
appositional growth
Conduction myofibers
are connected to each other via gap junctions
Osteoclasts
are stimulated by estrogen
A lack of the tunica externa best describes which of the following types of blood vessels:
arteriole
Which of the following can be found in bone tissue but NOT in cartilage
blood vessels
Which of the following respiratory structures DOES NOT demonstrate the presence of cartilage?
bronchiole
Number 50: Identify :
c-shaped cartilage ring
Number 48: Identify
capillary
The term used to describe the collection of fluid within the pericardial cavity restricting the beating of the heart is
cardiac tamponade
A tissue matrix which demonstrates collagen fibers, proteoglycans such as chondroitin sulfate, and lacks blood vessels best describes:
cartilage
Perichondrium is absent from which of the following locations or structures
cartilage covering the joint surfaces of bone
Identify the cells marked by the arrows
chondroblast
Identify the cell marked by the black arrow
chondrocyte
Which of the following types of fibers are predominant fibers in elastic cartilage?
collagen and elastic fibers
Which of the following fibers found in 'fibrous' connective tissue are also found in bone?
collagen fibers
The predominant fiber located in the area labeled A is ?
collagen fibers of the percondrium
Decreased HYDROSTATIC pressure (increased blood pressure) causes _____ fluid loss from capillaries to extracellular fluid
decreased
The periosteum is formed of which of the following tissues?
dense regular connective tissue
Which of the following structures contains the 'medullary cavity'?
diaphysis
Identify the tissue marked by the white asterisk(s) .
elastic cartilage
The flap (pinna or auricle) of the ear is formed primarily of
elastic cartilage
Which of the following types of leukocytes function to breakdown histamine and phagocytize parasites
eosinophil
The most abundant blood cells in the body are:
erythrocytes
Which of the following cell types is found within the perichondrium?
fibroblast
Which of the following tissues is tough, compresses only slightly under pressure force, demonstrates collagen fibers visible in the light microscope, demonstrates cells found in lacunae
fibrocartilage
Which of the following types of cartilage contributes to the structure of pubic synphysis in the spinal column
fibrocartilage
The bundle of His
fires at the rate of approximately 15-20 X minute
Diarthrosis
freely movable joint
Which of the following tests measures the ratio total cell volume to total blood volume?
hematocrit
Number 53: Identify the tissue be specific
hyaline
Identify the tissue illustrated in this slide.
hyaline cartilage
Identify the tissue marked A.
hyaline cartilage
Identify the tissue marked with the letter B.
hyaline cartilage
