Adenohypophysis
Acidophils. Hormone-containing granules in the cytoplasm stain with acidic dyes, e.g., eosin Somatotropes. Secrete somatotropin, growth hormone, GH which promotes growth anabolic Mammotropes. Secrete prolactin which stimulates milk production Basophils. Hormone-containing granules in the cytoplasm of these cells stain with basic dyes, e.g., hematoxylin Thyrotropes. Secrete thyroid stimulating hormone TSH which stimulates thyroid hormone synthesis and release Gonadotropes. Secrete luteinizing...
Functional Microanatomy
A variation of discontinuous capillaries, in that gaps exist between endothelial cells and the fenestrations lack diaphragms The basal lamina is lacking beneath the fenestrations. Fenestrations open into a subsinusoidal space, the space of Disse, separating the sinusoids from the hepatocytes beneath the space. Kupffer cells, liver macrophages, span the sinusoids, filtering debris from the blood. Arranged as walls one to two cells thick that radiate out from the central vein like the spokes of...
Vascular Supply to Lungs
Pulmonary circulation supplies deoxygenated blood for gas exchange The pulmonary artery and its branches travel adjacent to the bronchial passageways, supplying deoxygenated blood to the pulmonary capillaries. Pulmonary arteries are comparable in diameter to their neighboring respiratory passageways. Alveolar pulmonary capillaries lie in the interalveolar septa, forming part of the air-blood barrier. These abundant capillaries anastomose to form pulmonary veins. figure 13.5. Vascular supply to...
Origins of the Pituitary Gland
The pituitary gland consists of two different glands, the adeno-hypophysis and the neurohypophysis, which are derived embry-ologically from two distinct tissues. The adenophypophysis develops from a hollow evagination, Rathke's pouch, an outgrowth of stomadeal ectoderm from the roof of the mouth. Rathke's pouch loses its connection with the oral cavity and ascends toward the base of the brain where it contacts the neurohypophysis. Pars distalis. Largest subdivision forms from the anterior wall...
Neurohypophysis
Infundibulum hypophyseal stalk Extension from the hypothalamus continuous with the pars nervosa Contains the hypothalamo-hypophyseal tract which consists of axons from neurons whose cell bodies are located in the supraoptic and paraventricular nuclei of the hypothalamus Contains axons and axon terminals of the neurons forming the hypothalamo-hypophyseal tract Herring bodies. Expanded axon terminals which accumulate secretory granules containing oxytocin or antidiuretic hormone Oxytocin causes...
Supportive cells
Supporting cells of the CNS neuroglial cells outnumber neurons 10 1 Fibrous astrocytes in white matter Protoplasmic astrocytes in gray matter Present in white and gray matter Interfascicular oligodendrocytes are located in the white matter of the CNS, where they produce the myelin sheath. Ependymal cells. Line ventricles Not a true neuroglial cell derived from mesoderm whereas neu-roglial cells, as well as neurons, are derived from ectoderm Supporting cells of the PNS. Schwann cells Satellite...
Stroma vs Parenchyma
Stroma. The supporting framework of an organ, usually composed of connective tissue Parenchyma. The cells and tissues of an organ that perform the function of the organ composed of epithelium, muscle, nerve and, sometimes, connective tissue Lamina propria Lumen Mesothelium Mucosa Muscularis externa Muscularis mucosae Peritoneal space Serosa Stroma and parenchyma Parenchyma Stroma
Dermis
Located immediately beneath the basement membrane of the epidermis, forming the dermal papillae Thin layer composed of loose connective tissue Contains small blood vessels, nerves, lymphatics, and the sensory receptors, Meissner's corpuscles Located between the papillary layer and the hypodermis Thick layer composed of dense, irregular connective tissue Contains larger nerves and blood vessels, glands, hair follicles, and the sensory receptors, Pacinian corpuscles and Ruffini end organs...
Classification of SkinBased on the Thickness of the Epidermis
Covers entire body except palms and soles 0.5 mm thick on the eyelid, 5 mm thick on the back and shoulders Epidermis is thin, 0.075-0.15 mm thick, but the dermis can be quite thick. Possesses hair with sebaceous glands Located on palms of the hands and soles of the feet 0.8-1.5 mm thick Epidermis is 0.4-0.6mm thick. Hairless and, thus, possesses no sebaceous glands Keratinocytes. Keratinizing epidermal cells, major cell type in the epidermis Melanocytes. Melanin pigment-producing cells...
Teeth
Anatomic crown. The portion of the tooth covered by enamel. Anatomic root. The portion of the tooth covered by cementum. Cervix. Region where enamel abuts cementum Pulp cavity is the central core of a tooth and is divided into a pulp chamber in the crown and a root canal in the root. An apical foramen at the tip of the root allows passage of nerves and blood vessels into and out of the pulp cavity. Gingiva. Oral mucosa encircling the cervical region of the tooth and providing support for the...
Myelin Sheath
The myelin sheath is formed by the plasma membrane of supporting cells wrapping around the axon. The sheath consists of multilamellar, lipid-rich segments produced by Schwann cells in the PNS and oligodendrocytes in the CNS. Functions Increases speed of conduction saltatory conduction Similar structure in CNS and PNS with some differences in protein Internode. Single myelin segment Paranode. Ends of each internode where they attach to the axon Node of Ranvier. Specialized region of the axon...
Connective Tissues with Special Properties
Adipose connective tissue. Consists of accumulations of adipocytes that are partitioned into lobules by septa of connective tissue proper. Provides energy storage and insulation Blood and hematopoietic blood-forming tissues Chapter 6 Elastic connective tissue. Regularly arranged elastic fibers or sheets e.g., the vocal ligament Reticular connective tissue. A loosely arranged connective tissue whose fibers are reticular fibers. Forms the stroma of hematopoietic tissue e.g., bone marrow and...
The Nephron
1.5-2 million per kidney Renal corpuscle Located in the cortical labyrinth Glomerulus. A tuft of fenestrated capillaries, whose pores lack diaphragms filter blood. Formed by an afferent arteriole, the glomerulus indents into Bowman's capsule like a baseball fits into a baseball glove. Blood leaves the glomerulus via the efferent arteriole. Bowman's capsule. Double-walled, epithelial capsule with central space called Bowman's space surrounds the glomerulus and receives the fluid filtered from...
Membranes
Definition. A layer of epithelium and its underlying connective tissue that covers a surface of the body. A membrane lines almost all surfaces of the body. Types of membranes Covers the exterior surface of the body. Stratified squamous keratinized epithelium called epidermis Two layers of connective tissue, loose connective tissue and dense irregular connective tissue, called the dermis May possess hair follicles, sweat glands, and sebaceous glands Lines all interior lumens of organs that open...
Veins
Return blood from capillary beds to the heart Have thinner walls and larger lumens than arteries of similar size cross-sectional outlines are more irregular Tunica adventitia is the predominate tunic. Larger veins possess valves, that are extensions of the tunica intima that serve to prevent back-flow of blood. Tunica media is absent in venules. Smooth muscle fibers appear in the tunica media as venules progress to small veins. High endothelial venules. Venules in which the endothelium is...
Cells of Connective Tissue
Connective tissue cells can be subdivided into two major groups. Resident cells are derived from mesenchyme and are continuously present in the tissue e.g., fibroblasts and adipocytes . Migratory cells enter and leave the blood stream to migrate through and function in connective tissues e.g., neutrophils and macrophages monocytes . figure 4.1. Components of connective tissue proper. Synthesize and maintain fibers and ground substance Major resident cell in connective tissue proper Active and...
Macroscopic Organization of the Kidney Cortex Broad outer zone of kidney
figure 15.1. Extrarenal passageways and vascular supply of the kidney. figure 15.1. Extrarenal passageways and vascular supply of the kidney. Labyrinth. True cortical tissue Medullary rays. Medullary tissue located in the cortex Consists of renal corpuscles, portions of renal tubules, and collecting ducts Renal pyramids. Inverted cones whose bases are adjacent to the cortex send stripes of medullary tissue into the cortex forming the medullary rays Renal columns. Extensions of cortical tissue...
Cardiac Muscle
Cardiac muscle occurs only in the myocardium of the heart and, to a variable extent, in the roots of large vessels where they join the heart. Structure of cardiac muscle fibers Intermediate in size between skeletal and smooth muscle Fibers are cylindrical, branch, and form interwoven bundles. Usually one nucleus per fiber located in the center Organelles are clustered at the poles of the nucleus. Myofilament organization into myofibrils is identical to skeletal muscle. Cross-striations and...
Alveoli
Alveoli are thin-walled, hollow polyhedrons forming the bulk of the lungs where gas exchange occurs. Alveoli are components of respiratory bronchioles and alveolar ducts, or they may be grouped together to form alveolar sacs. Interalveolar septum. Structure between two adjacent alveoli is composed of The epithelium lining each alveolus. Squamous alveolar or type I cells form a simple squamous epithelium lining 95 of the alveolar surface area and forming a portion of the blood-air barrier....
general Concepts Rjb
Muscle tissue is specialized for the ability to shorten or contract. While all cells possess the cellular machinery necessary for shape change and contraction, these structures are significantly more prominent in muscle cells. For some muscle types, the cells are nonproliferative due to this high degree of specialization and differentiation. Muscle contraction is accomplished by the reciprocating sliding of intracellular filaments composed of actin and myosin. Muscle tissue comprises the flesh...
Components of the Lymphoid System
Located in lamina propria of any organ system opening to the exterior of the body, such as respiratory and digestive systems, where an antigen could penetrate the epithelium and enter the lamina propria. Diffuse lymphoid tissue in the lamina propria is part of the mucosal-associated lymphoid tissue MALT . Diffuse lymphatic tissue is also located in tonsils, lymph nodes, and spleen. Composed of an unorganized cluster of lymphocytes and other cells capable of responding to an antigen that...
Exocrine vs Endocrine Glands
Major classification of glands, which is based on the method by which their secretory product is distributed Secretory products are released onto an external or internal epithelial surface, either directly or via a duct or duct system. Secretory cells display polarized distribution of organelles. No ducts secretory products are released directly into the extracellular fluid where they can affect adjacent cells paracrine secretion or enter the bloodstream to influence cells throughout the body...
general Concepts Hgy
Provides immune surveillance and defense against foreign substances and microorganisms Provides immune tolerance, distinguishing between self and non-self Absorbs lipids into small lymphoid vessels lacteals in intestinal villi for distribution to the blood stream and liver Helps to maintain fluid balance by accumulating tissue fluid and white blood cells in lymph vessels and returning them to the blood Primary lymphoid organs and structures Bone marrow. Site of origin of T and B lymphocytes. B...
Structures Associated with the Skin
Simple, coiled tubular glands Contain myoepithelial cells, which are specialized cells that contract to aid in the expulsion of the sweat Merocrine or eccrine. Located in all regions of the body except the axillary and anal regions produce a watery secretion that empties onto the surface of the epidermis Apocrine. Restricted to the axillary, areolar, and anal regions much larger than eccrine sweat glands with a broader lumen. Produce a viscous secretion that empties into the hair follicle. Do...
Components of the Respiratory System
In relationship to lungs listed in order from exterior to interior, i.e., the path of inspired air According to function listed in order from exterior to interior Conducting Portion Transports air from exterior Respiratory Portion Involved with gas exchange Structure of Typical Respiratory Passageways Conducting portion nasal cavities through secondary bronchi Mucosa mucous membrane . Faces the lumen Respiratory epithelium. Pseudostratified with cilia and goblet cells. Lamina propria of loose...
Duct System of Compound Exocrine Glands
Intralobular ducts. Contained within a lobule simple cuboidal to columnar epithelium Interlobular ducts. Receive numerous intralobular ducts located in the connective tissue between lobules stratified columnar epithelium Excretory main duct. Macroscopic duct draining the entire gland Intralobular CT _J__ _ . Excretory main Intralobular CT _J__ _ . Excretory main Se cretory I ntra lo b u ta r d ucts I nterl obu I ar d u ct Se cretory I ntra lo b u ta r d ucts I nterl obu I ar d u ct figure 3.4....
Components 1
figure 12.1. Organs comprising the tubular digestive tract. figure 12.1. Organs comprising the tubular digestive tract. Stomach Small intestine Large intestine Basic Histological Organization Layers Mucosa mucous membrane . Innermost layer facing the lumen Epithelium. Either a stratified squamous moist or a simple columnar epithelium Lamina propria. Loose connective tissue usually possesses digestive glands Muscularis mucosae of smooth muscle is usually present. Submucosa. Denser connective...
Is lined with an endosteum
Concentric lamellae 4-20 surround the Haversian canal. Collagen fibers are in parallel alignment within a single lamella, wrapping helically around the Haversian canal. Pitch of the helix varies with each lamella in the osteon. Provides great strength to a long bone An osteon is formed by the centripetal deposition of the concentric lamella i.e., outer lamella is the oldest . Additional lamellae structures associated with adult, compact lamellar bone Interstitial lamellae. Portions of...
Structure of a Typical Neuron
Large, spherical, usually centrally located in the soma Highly euchromatic with a large, prominent nucleolus Well-developed cytoskeleton Intermediate filaments neurofilaments . 8-10nm in diameter Microtubules. 18-20nm in diameter Abundant rough endoplasmic reticulum and polysomes Nissl substance Well-developed Golgi apparatus Numerous mitochondria Dendrite s Usually multiple and highly branched at acute angles May possess spines to increase surface area for synaptic contact Collectively, form...
Heart
Consists of an endothelium simple squamous epithelium plus underlying connective tissue Cardiac valves. Folds of the endocardium Semilunar valves at the base of the aortic and pulmonary trunks prevent backflow of blood into the heart. Atrioventricular valves bicuspid and tricuspid prevent backflow of blood from the ventricles into the atria. Fibers insert on components of the cardiac skeleton. Thickest layer of the heart Variation in thickness depends on the function of each chamber thicker in...
Architecture of a Long Bone
The diaphysis shaft , composed of compact bone, is hollow and is usually lined by a thin band of spongy bone. An epiphysis, the knob at either end of the diaphysis, is composed of a thin rim of compact bone. The spongy bone in its interior houses red marrow. Metaphysis. Flared region between diaphysis and epiphysis. Epiphyseal plate. Hyaline cartilage separating epiphysis and metaph-ysis in growing bones. Growth in bone length occurs as hyaline cartilage in the epiphyseal plate goes through...
Cell Junctions
Specialized structures of the plasma membrane that Establish apical and basolateral membrane domains by sealing adjacent plasma membranes Provide channels for ionic and metabolic coupling Not restricted to epithelial cells cell junctions occur, however, in large number in epithelial tissues to resist the physical forces acting on the cells. figure 3.2. Cell junctions and surface specializations. figure 3.2. Cell junctions and surface specializations. Tight junction zonula occludens Belt-like,...
Classification of Exocrine Glands
Unicellular glands. Individual cells located within an epithelium, such as goblet cells that secrete mucus Multicellular glands Sheet gland. Composed of a surface epithelium in which every cell is a mucus-secreting cell. A sheet gland is unique to the lining of the stomach. The remaining multicellular glands are classified according to The shape s of the secretory units Presence of acini singular, acinus or alveoli singular, alveolus these two terms are synonymous , which are flask-shaped...
Types of Lining and Covering Epithelium Simple epithelial tissues Simple
Allows for rapid diffusion across the epithelium figure 3.1. Types of lining and covering epithelia. figure 3.1. Types of lining and covering epithelia. Forms the lining of blood vessels, alveoli of the lungs, and internal body cavities Forms the walls of ducts and tubules Forms the lining of the intestines and gall bladder Cells are of various heights. All cells rest on the basement membrane, but only the tallest cells reach the free surface. Variation in height of the cells and the location...