Selected Photomicrographs

Hashimoto thyroiditis, normal thyroid, and Graves disease (Figure 21-2) Figure 21-2. (A) Light micrograph of Hashimoto thyroiditis (HT). HT is characterized by a high lymphocytic infiltration that may form lymphoid follicles with germinal centers (L). Normal thyroid follicles (TF) also are observed. (B) Light micrograph of a normal thyroid gland showing numerous thyroid follicles (TF) containing colloidal material. The follicles are lined by follicular cells arranged as a simple cuboidal...

Blood

PLASMA is the fluid portion of blood that contains many different proteins, such as albumin, which maintains blood colloidal osmotic (oncotic) pressure gamma globulins beta globulins, which participate in the transport of hormones, metal ions, and lipids and fibrinogen, which participates in blood clotting. Plasma without fibrinogen is called serum. II. RED BLOOD CELLS (RBCs or erythrocytes) 1. RBCs do not contain a nucleus or mitochondria. 2. RBCs use glucose as the primary fuel source...

Urinary System

RENAL (URINIFEROUS) TUBULES (Figure 19-1) are the structural and functional units of the kidney and consist of a nephron and a collecting duct. II. NEPHRONS consist of the following A. The renal glomerulus is a capillary network that receives blood from an afferent arteriole (major site of autoregulation of blood flow) and is drained by an efferent arteriole. 1. It contains a mesangium (extracellular matrix between capillaries) and mesangial cells, which have a phagocytic function, as well...

Tympanic Membrane Eardrum consists of three layers

Keratinized stratified squamous epithelium covers the external surface. B. Connective tissue that is vascularized and innervated constitutes the middle layer. C. Simple squamous epithelium covers the internal surface. II. MEMBRANOUS LABYRINTH is contained within the osseous labyrinth. The membranous labyrinth is filled with endolymph. The osseous labyrinth is filled with perilymph. A. Kinetic labyrinth (semicircular ducts Figure 27-1A) 1. Type I and type II hair cells within cristae...

Respiratory System

This portion of the respiratory system only conducts air into the lungs. No blood-air gas exchange occurs in this portion. A. Contents. The conduction portion consists of the trachea, bronchi, bronchioles, and terminal bronchioles. 1. The trachea and bronchi are lined by a respiratory epithelium, which is classically described as a ciliated pseudostratified epithelium with goblet cells that contains the following cell types a. Ciliated cells beat toward the pharynx,...

Viclinical Considerations

Complete androgen insensitivity (CA1S testicular feminization syndrome) is caused by a mutation in the androgen receptor (AR) gene that renders the AR inactive. It is the most common cause of male pseudointersexuality. 1. Normally, the AR is a nuclear transcription factor that is activated by androgens to bind DNA promoter regions that regulate transcription of other genes. 2. CAIS produces the following clinical findings 46,XY genotype and undescended testes, but normal-appearing female...

Vclinical Considerations

Graves disease is hyperthyroidism caused by a diffuse, hyperplastic goiter. 1. It is relatively common in women. 2. It is an autoimmune disease that produces TSH receptor-stimulating autoantibodies. 3. It is characterized clinically by ophthalmopathy (lid stare, eye bulging), heat intolerance, nervousness, irritability, and weight loss in the presence of a good appetite. B. Secondary hyperthyroidism is relatively uncommon and may be caused by a TSH adenoma in the adenohypophysis. C....

Iiismooth Muscle

Smooth muscle fibers (cells) have the following characteristics 1. They have cytoplasmic dense bodies (equivalent to Z disks), which contain -actinin 2. Smooth muscle fibers have subplasmalemmal dense plaques, which contain vin-culin and talin 3. Smooth muscle fibers contain actin and myosin filaments, as well as desmin and vimentin intermediate filaments (Vimentin is found predominately in vascular smooth muscle.) 4. They have numerous invaginations of the cell membrane called caveolae...

Ithyroid Follicles

Thyroid follicles are hounded by follicular cells and parafollicular cells. B. They are filled with a colloid that consists of iodinated thyroglobulin. II. FOLLICULAR CELLS (Figure 21-1). These cells A. Contain thyroid-stimulating hormone (TSH) receptors C. Secrete thyroglobulin into the follicular lumen D. Take up iodide (I-) from the blood using a Na+-1 cotransporter and transport it to the follicular lumen E. Oxidize iodide (2I + H207 > I7) using the enzyme thyroid peroxidase and...

Iiclassification Table

POLARITY of an epithelial cell is made evident by specializations that are found in various regions of the cell (Figure 2-1). 1. Microvilli contain a core of actin filaments that are anchored to the terminal web. The actin filaments are cross-linked by villin. Microvilli of intestinal epithelium are coated with a glycocalyx that consists of terminal oligosaccharides of integral membrane proteins. The glycocalyx has enzymatic activity involved in carbohydrate digestion. 2. Stereocilia are...

Table 211

Laboratory Findings Used for Diagnosis of Thyroid Disorders Low TSH secretion by Low adenohypophysis or low TRF secretion by the hypothalamus DES diethylstilbestrol FT4 free thyroxine RT3U resin T3 uptake test T3 triiodothyronine T4 thyroxine TRF thyrotropin-releasing factor TSH thyroid-stimulating hormone. The resin T3 uptake (RT3U) test is not a measure of serum T3 levels rather, it evaluates thyroid-binding globulin (TBG) levels via a competition assay between a resin and TBG for radioactive...

Vcervix

During prepuberty, the ectocervix protrudes into the vagina and is covered by a nonkeratinized, stratified squamous epithelium that is continuous with the vaginal epithelium. B. The endocervical canal connects the uterine cavity with the vaginal cavity and is lined by deep crypts of mucous-secreting simple columnar epithelium. 1. At puberty, the simple columnar epithelium of the endocervical canal extends onto the ectocervix. However, exposure of the simple columnar epithelium to the acidic...

Connective Tissue

Types of connective tissue include loose connective tissue (e.g., fascia, lamina propria), dense connective tissue (e.g., tendons), adipose tissue, cartilage, and bone. The common features of all connective tissues are the ground substance, fibers, and cells, as described below. II. GROUND SUBSTANCE contains the following components A. Proteoglycans consist of a core protein, which binds many side chains of gly-coaminoglycans (GAGs), and a link protein, which binds hyaluronic...

Female Reproductive System

ADULT OVARY (CORTEX) contains follicles in various stages of development, including the primordial follicle, primary follicle, secondary follicle, and Graafian follicle. Follicles are composed of an oocyte, follicular cells, and thecal cells (Table 24-1). II. CORPUS LUTEUM is a temporary endocrine gland. Its formation is dependent on A. Development. Corpus luteum develops from the granulosa cells and theca interna cells of the Graafian follicle after the secondary oocyte is ovulated through...

Lymph Node

OUTER CORTEX consists of the following A. B cells (see Chapter 9 V E), which are organized into lymphatic follicles that may contain germinal centers (these are evidence of an immune response whereby B cells are transformed into plasma cells) C. Follicular dendritic cells, which have an antigen-presenting function E. Fibroblasts (reticular cells), which secrete type III collagen (reticular fibers) that form a stromal meshwork II. INNER CORTEX (paracortex thymic-dependent zone) consists of...

Nervous Tissue

THE NEURON is the structural and functional unit of the nervous system. The neuron consists of a perikaryon cell body , dendrite, and axon, each of which contains certain ul-trastructural components Table 7-1 . The axon arises from an extension of the perikaryon called rhe axon hillock. The part of the axon between the axon hillock and the start of the myelin sheath is called the initial segment and is where the action potential is initiated. 1. Fast anterograde transport is responsible for...