Medical Laboratory

My name is Jacob and I am a histologist. This blog is centered on histology, forensic, autopsy, clinical, and surgical pathology.

[biomedicool]

Lymph Nodes

Lymph nodes are organs with a collagenous capsule, which are frequently found within adipose tissue.

They are strategically placed along the lymphatic network. Here they can trap foreign material (antigens), which are presented to the lymphocytes by antigen-presenting cells, to initiate an immune response.

The cortex contains primary lymphoid follicles and secondary follicles, which contain  densely packed lymphocytes. They have a distinct mantle zone and a paler-staining germinal centre.

The tissue is organised both to facilitate the interactions needed to generate an immune response against the antigen, and to promote rapid division of the responding lymphocytes.

Nodes vary in size (from a few millimetres to 1–2 cm)

Distributed in different areas of the body.

Linked in chains by lymphatic ducts, so that fluid flowing out of one lymph node via the efferent lymphatic vessel becomes the inflow to the next in line, via the afferent lymphatics.

Fluid = lymph,  derived from the tissue that carries cells and foreign material to the lymph nodes. 

Lymph returns to the bloodstream via one of the body’s two major lymphatic ducts.

Can be considered guard posts that are strategically placed to intercept any infectious agent that enters an area of the body. 

So, for example, the lymph nodes in the axilla of the arm (the armpit) will intercept infections which enter that part of the body.

Lymphocytes located in the local lymph nodes are responsible for the initial recognition of the infection and the development of the immune response. 

Once the immune response has developed, cells will migrate out from the lymph node into the blood 

move to the site of infection to combat the pathogen there.

Lymph nodes have a well defined structure with different sub-regions. 

Antigens and cells enter the node through afferent lymphatics

cells and fluid leave through the efferent lymphatic. 

Cells (lymphocytes) can also enter the node from the blood by migrating across the specialised high endothelial venules. 

Within the node, cells distribute themselves to distinct zones. 

B cells proliferate and develop within the follicles of the cortex,

T cells are primarily located in the paracortex. 

The capsule, medullary cords and hilus are fixed structural elements of the tissue.

[orqueen]

The Cervical Spinal Cord And Its Nerves. By removing the rear arches of the neck, vertebra and the fibrous covering over the spinal cord, one sees the cervical spinal cord and its nerves. The blood vessels nourishing the cord and vertebral column and the origin of the cord from the brain are clearly shown.

[the-art-of-medicine]

Upper Respiratory Tract

Here’s looking at you, @queen-of-darkness13! Thank you for the request!

[medlabscience]

Just in case you get a cold or throat infection and would like to know what is what. The trachea continues along the pulmonary system, strategically branching off before connecting to the lungs.

[microscope-world]

This is the fundic region of the stomach captured under a lab microscope at 40x magnification.

[labtechnition-blog]

What is cholesterol?

Cholesterol is a waxy, fat-like substance that’s found in all the cells in your body. Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods. Your body makes all the cholesterol it needs. Cholesterol is also found in foods from animal sources, such as egg yolks, meat, and cheese.

If you have too much cholesterol in your blood, it can combine with other substances in the blood to form plaque. Plaque sticks to the walls of your arteries. This buildup of plaque is known as atherosclerosis. It can lead to coronary artery disease, where your coronary arteries become narrow or even blocked.

What are LDL, HDL, and VLDL?

There are different types of cholesterol:

HDL stands for high-density lipoprotein. It is called the “good” cholesterol because it carries cholesterol from other parts of your body back to your liver. Your liver then removes the cholesterol from your body.

LDL stands for low-density lipoprotein. It is called the “bad” cholesterol because a high LDL level leads to the buildup of plaque in your arteries.

VLDL stands for very low-density lipoprotein. It is also a “bad” cholesterol because it too contributes to the buildup of plaque in your arteries. But VLDL and LDL are different; VLDL carries triglycerides and LDL carries cholesterol.

What causes high cholesterol?

The most common cause of high cholesterol is an unhealthy lifestyle. This can include

Unhealthy eating habits, such as eating lots of bad fats. One type, saturated fat, is found in some meats, dairy products, chocolate, baked goods, and deep-fried and processed foods. Another type, trans fat, is in some fried and processed foods. Eating these fats can raise your LDL (bad) cholesterol.

Lack of physical activity, with lots of sitting and little exercise. This lowers your HDL (good) cholesterol.

Smoking, which lowers HDL cholesterol, especially in women. It also raises your LDL cholesterol.

Genetics may also cause people to have high cholesterol. For example, familial hypercholesterolemia (FH) is an inherited form of high cholesterol. Other medical conditions and certain medicines may also cause high cholesterol.

What can raise my risk of high cholesterol?

A variety of things can raise your risk for high cholesterol:

Age. Your cholesterol levels tend to rise as you get older. Even though it is less common, younger people, including children and teens, can also have high cholesterol.

Heredity. High blood cholesterol can run in families.

Weight. Being overweight or having obesity raises your cholesterol level.

Race. Certain races may have an increased risk of high cholesterol. For example, African Americans typically have higher HDL and LDL cholesterol levels than whites.

Weight. Being overweight or having obesity raises your cholesterol level.

What health problems can high cholesterol cause?

If you have large deposits of plaque in your arteries, an area of plaque can rupture (break open). This can cause a blood clot to form on the surface of the plaque. If the clot becomes large enough, it can mostly or completely block blood flow in a coronary artery.

If the flow of oxygen-rich blood to your heart muscle is reduced or blocked, it can cause angina (chest pain) or a heart attack.

Plaque also can build up in other arteries in your body, including the arteries that bring oxygen-rich blood to your brain and limbs. This can lead to problems such as carotid artery disease, stroke, and peripheral arterial disease.

#sarbjeetjagraon

[ihearthisto]

😛 Drunk Hepatocyte 😛

Go home liver you are intoxicated!

i♡histo

Hepatocytes are the cells that form our liver. They are particularly talented cells because it is their job to metabolize and detoxify all of the substances that we eat or drink. Everything that is absorbed via our digestive tract makes its way into the hepatic portal vein and is shuttled through our liver before being given the all clear for release into the general circulation. In addition, hepatocytes store glucose as glycogen and can release glucose from these stores when blood sugar levels are low and we need it elevated. If that wasn’t enough, they also make bile! The green substance that is stored in the gallbladder and released into the duodenum to aid the digestion and absorption of the fats in our food.

📷 by Armando La Rosa

[microscope-world]

Cirrhosis of the liver captured under the clinical microscope at 400x.

[doctorforensic]

Tetracycline staining of the teeth due to exposure to this antibiotic as a child. This discoloration may be helpful as a feature for identification when other modalities are not possible. This discoloration, superior to the arrow, occurred during childhood when the teeth were still forming.

[doctorforensic]

This individual died of acute cocaine intoxication. He had a history of using cocaine chronically on and off for years. Note the perforated nasal septum associated with chronic cocaine abuse due to vessel constriction and decreased blood flow.

[ihearthisto]

✨🌐 Happy Star Wars Day 2018 🌐 ✨

 May the Fourth be with you! i♡histo Star Wars montage from top left clockwise: 1. The Graafian follicle Death Star In a galaxy far, far away an intergalactic superweapon is ready to be ovulated 2. Jabba the Corpus Albicans “makingsa lee ka bok pateesa… beeska chata wnow kong bantha poodoo” “you may have been a good friend..but now you are bantha fodder” The corpus albicans is a structure in the ovary that is formed when the corpus luteum regresses. 3. Tusken Raider Liver Despite what you see here, Tusken Raiders are not native to the human liver. If you think that, then you are making a wookie mistake. 4. The Empire is striking back (at the Liver) Liver histology is definitely where it’s At-At!

[doctorforensic]

A fulminant pulmonary edema with foam extending from the mouth and nose due to congestive heart failure in this individual with past history of viral myocarditis. A foam cone in a younger individual should always first arouse the suspicion of opiate overdose in the absence of known heart disease.

Note the frothy fluid from pulmonary edema extending into the laryngeal airway.

[doctorforensic]

Hepatocellular carcinoma associated with hepatic cirrhosis due to hepatitis B infection. Note the macronodular cirrhosis and the larger tumor nodules.

[doctorforensic]

Aorta with slight atherosclerosis. Note the fatty streaks on the intimal surface from this individual in their early 20s.

[biomedicool]

Cell Cycle - Cancer

Quiescent/ senescent 

Gap 0/G0 

A resting phase where the cell has left the cycle and has stopped dividing. 

Interphase

 Gap 1 / G1 

Cells increase in size. The G1 checkpoint control mechanism ensures that everything is ready for DNA synthesis. 

DNA Synthesis / S 

DNA replication occurs during this phase. 

Gap 2 / G2 

During the gap between DNA synthesis and mitosis, the cell will continue to grow. The G2 checkpoint control mechanism ensures that everything is ready to enter the M (mitosis) phase and divide. 

Cell division 

Mitosis / M 

Cell growth stops at this stage and cellular energy is focused on the orderly division into two daughter cells. 

A checkpoint in the middle of mitosis (Metaphase Checkpoint) ensures that the cell is ready to complete cell division. 

Cyclins 

family of proteins control cells through the cell cycle by activating cyclin-dependent kinases (CDKs). 

G1 /S cyclins – essential for the control of the cell cycle at the G1/S transition, Cyclin D/ CDK4, Cyclin D /CDK6, and Cyclin E / CDK2 – regulates transition from G1 to S phase. 

G2 /M cyclins – essential for the control of the cell cycle at the G2/M transition (mitosis). G2 /M cyclins accumulate steadily during G2 and are abruptly destroyed as cells exit from mitosis. Cyclin B / CDK1 – regulates progression from G2 to M phase 

[doctorforensic]

Petechiae associated with heart disease and resuscitation.

[doctorforensic]

Severely stenotic and insufficient aortic valve associated with childhood rheumatic fever. Correction of aortic stenosis will decrease the risk of sudden cardiac death.

[biomedicool]

Breast Cytology

The adult female breast is a modified sweat gland consisting of 15-25 lobes 

each lobe composed of several lobules 

each lobule consists of compound ducts which drain into a large lactiferous duct, one per lobe 

secretory acini develop from the lobular ducts in pregnancy 

ducts are lined by cuboidal and columnar epithelium 

Fine Needle Aspiration (FNA) was the most common cytological specimen until a recent increase in use of automated core needle biopsy (CNB) which gives histological material 

FNA is cheaper and easier than an excisional biopsy 

however, FNA has a higher non-diagnostic rate than CNB (less accurate) and accuracy is highly operator dependent 

sensitivity for malignancy is 65% - 98% 

CNB can significantly decrease health care costs by decreasing the number of open surgical biopsies without sacrificing early detection 

when diagnosis is benign, FNA saves the patient having to endure surgical biopsy 

diagnosis of malignancy allows pre-operative discussion of available treatment options (e.g. lumpectomy with radiation versus mastectomy) 

it might also persuade a reluctant patient to undergo surgical biopsy 

Benign Conditions

fibrocystic change the most common 

Characterised by small or large cysts, apocrine metaplasia, focal fibrosis, intraductal hyperplasia 

Fibroadenoma: the most common benign tumour of the female breast 

 well circumscribed (within limits - eg stays in epithelium), freely movable, rubbery masses that result from both stromal and glandular proliferation 

Breast cancer 

Invasive Ductal Carcinoma (most common form of breast cancer), approx. 65-80% 

Invasive Lobular Carcinoma: 5% of cases 

Medullary Carcinoma: 5-7% 

Mucinous (colloid) Carcinoma: 2% 

Tubular Carcinoma: <2% 

Metaplastic Carcinoma: <5%