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Help with Histology DrPhil 117 Views • 3 years ago

How to approach histology for Human Anatomy students. Using a key will help get you through it! Add some penguin fairy dust will help too!

Please note: I mis-spoke and said "striated" instead of "stratified epithelium" a couple of times... apologies!

There are lots of histology keys out there, but the one I showed in the video is here: http://www.penguinprof.com/upl....oads/8/4/3/1/8431323

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Details:

Tissue in the human body:

Epithelial: Is made of cells arranged in a continuous sheet with one or more layers, has apical & basal surfaces.

A basement membrane is the attachment between the basal surface of the cell & the underlying connective tissue.

Two types of epithelial tissues: (1) Covering & lining epithelia and (2) Glandular Epithelium.

The number of cell layers & the shape of the cells in the top layer can classify epithelium.

Simple Epithelium - one cell layer
Stratified epithelium - two or more cell layers
Pseudostratified Columnar Epithelium - When cells of an epithelial tissue are all anchored to the basement Membrane but not all cells reach the apical surface.
Glandular Epithelium -- (1) Endocrine: Release hormones directly into the blood stream and (2) Exocrine - Secrete into ducts.

Connective: contains many different cell types including: fibroblasts, macrophages, mast cells, and adipocytes. Connective Tissue Matrix is made of two materials: ground substance - proteins and polysaccharides, fiber -- reticular, collagen and elastic.

Classification of Connective Tissue:
Loose Connective - fibers & many cell types in gelatinous matrix, found in skin, & surrounding blood vessels, nerves, and organs.
Dense Connective - Bundles of parallel collagen fibers& fibroblasts, found in tendons& ligaments.
Cartilage - Cartilage is made of collagen & elastin fibers embedded in a matrix glycoprotein & cells called chondrocytes, which was found in small spaces.
Cartilage has three subtypes:
Hyaline cartilage -- Weakest, most abundant type, Found at end of long bones, & structures like the ear and nose,
Elastic cartilage- maintains shape, branching elastic fibers distinguish it from hyaline and
Fibrous Cartilage - Strongest type, has dense collagen & little matrix, found in pelvis, skull & vertebral discs.

Muscle: is divided into 3 categories, skeletal, cardiac and smooth.
Skeletal Muscle -- voluntary, striated, striations perpendicular to the muscle fibers and it is mainly found attached to bones.
Cardiac Muscle -- involuntary, striated, branched and has intercalated discs
Smooth Muscle -- involuntary, nonstriated, spindle shaped and is found in blood vessels & the GI tract.

Nervous: Consists of only two cell types in the central nervous system (CNS) & peripheral nervous system (PNS):
Neurons - Cells that convert stimuli into electrical impulses to the brain, and Neuroglia -- supportive cells.
Neurons -- are made up of cell body, axon and dendrites. There are 3 types of neurons:
Motor Neuron -- carry impulses from CNS to muscles and glands,
Interneuron - interpret input from sensory neurons and end responses to motor neurons
Sensory Neuron -- receive information from environment and transmit to CNS.
Neuroglia -- is made up of astrocytes, oligodendrocytes, ependymal cells and microglia in the CNS, and schwann cells and satellite cells in the PNS.

Aortic Aneurysm 3D Animation Mohamed 18,450 Views • 3 years ago

Most intact aortic aneurysms do not produce symptoms. As they enlarge, symptoms such as abdominal pain and back pain may develop. Compression of nerve roots may cause leg pain or numbness. Untreated, aneurysms tend to become progressively larger, although the rate of enlargement is unpredictable for any individual. Rarely, clotted blood which lines most aortic aneurysms can break off and result in an embolus. They may be found on physical examination. Medical imaging is necessary to confirm the diagnosis. Symptoms may include: anxiety or feeling of stress; nausea and vomiting; clammy skin; rapid heart rate. In patients presenting with aneurysm of the arch of the aorta, a common symptom is a hoarse voice as the left recurrent laryngeal nerve (a branch of the vagus nerve) is stretched. This is due to the recurrent laryngeal nerve winding around the arch of the aorta. If an aneurysm occurs in this location, the arch of the aorta will swell, hence stretching the left recurrent laryngeal nerve. The patient therefore has a hoarse voice as the recurrent laryngeal nerve allows function and sensation in the voicebox. Abdominal aortic aneurysms, hereafter referred to as AAAs, are the most common type of aortic aneurysm. One reason for this is that elastin, the principal load-bearing protein present in the wall of the aorta, is reduced in the abdominal aorta as compared to the thoracic aorta (nearer the heart). Another is that the abdominal aorta does not possess vasa vasorum, hindering repair. Most are true aneurysms that involve all three layers (tunica intima, tunica media and tunica adventitia), and are generally asymptomatic before rupture. The most common sign for the aortic aneuysm is the Erythema nodosum also known as leg lesions typically found near the ankle area. The prevalence of AAAs increases with age, with an average age of 65–70 at the time of diagnosis. AAAs have been attributed to atherosclerosis, though other factors are involved in their formation. An AAA may remain asymptomatic indefinitely. There is a large risk of rupture once the size has reached 5 cm, though some AAAs may swell to over 15 cm in diameter before rupturing. Before rupture, an AAA may present as a large, pulsatile mass above the umbilicus. A bruit may be heard from the turbulent flow in a severe atherosclerotic aneurysm or if thrombosis occurs. Unfortunately, however, rupture is usually the first hint of AAA. Once an aneurysm has ruptured, it presents with a classic pain-hypotension-mass triad. The pain is classically reported in the abdomen, back or flank. It is usually acute, severe and constant, and may radiate through the abdomen to the back. The diagnosis of an abdominal aortic aneurysm can be confirmed at the bedside by the use of ultrasound. Rupture could be indicated by the presence of free fluid in potential abdominal spaces, such as Morison's pouch, the splenorenal space (between the spleen and left kidney), subdiaphragmatic spaces (underneath the diaphragm) and peri-vesical spaces. A contrast-enhanced abdominal CT scan is needed for confirmation. Only 10–25% of patients survive rupture due to large pre- and post-operative mortality. Annual mortality from ruptured abdominal aneurysms in the United States alone is about 15,000. Another important complication of AAA is formation of a thrombus in the aneurysm.

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