Liver Right Side Abdominal Cavity Beneath The Diaphragm Biology Essay

Published:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

It is the largest glandular organ divided into four lobes of unequal size and shape. It lies on the right side of abdominal cavity beneath the diaphragm. An exocrine gland secretes the bile juice into the intestine for digestion of fats. The main function of the liver is to produce substance that break down fats, convert glucose to glycogen, make certain amino acids, filter harmful substance from the blood and maintain proper level of glucose in blood.

Cigarette smoke encounter liver, it indirectly affects it. The chemicals in cigarette live hydrocarbons and vinyl chloride are carcinogens, which causes cancer. They also cause oxidative stress and it leads to the damage to the liver cells and fibrosis. The chemicals prevent the liver from performing its main function. Over time, the organ becomes less efficient in removing the toxins from the body.

The main type of cancer caused due to smoking is Hepatic cell carcinoma, which is due to the accumulation of excess iron in the hepatocytes. This induces fibrosis and favors the development of the cancer.

Histology

The liver is bound by a connective tissue capsule, which is then extended as highly branched septae. The liver is divided into four lobes based on surface features. It is divided into right anatomical and left anatomical lobe by the falciform ligament. The other two lobes are the caudate lobe and quadrate lobe. These lobes are further divided as lobules the structural unit of liver. The lobules are hexagonal in shape, with portal triads at the vertices and central vein in the middle.

The parenchyma cells of the liver are known as hepatocytes. They are polygonal in shape and are arranged as hepatic chords, which are separated by vascular sinusoids. Special cells called Kupffer cells are associated with the sinusoids, which act as liver macrophages to effectively kill the bacteria that enter through blood. The space between the endothelium and the hepatocytes is called the Space of Disse, which collects lymph and transports it to the lymphatic capillaries.

The hepatocytes produce the bile and it is collected in channels called canaliculi. These secretions flow to the periphery of lobules and then to the bile ductules and interlobular bile ducts, ultimately into the hepatic duct which is present outside the liver. The hepatic duct then continues with the common bile duct, that delivers bile into the duodenum or temporarily stored in the gallbladder through the cystic duct.

Fig.1. Liver histology

Mechanism

Smoking causes cytotoxic effects by the release of certain chemicals. They cause oxidative stress, which in turn leads to the activation of satellite cells and hence leading to fibrosis. The production of pro-inflammatory cytokines such as IL-1, IL-6 and TNF-alpha are increased by smoking which in turn causes liver cell injury in the form of necroinflammation, apoptosis and excess iron deposition. Excess iron deposition in the hepatocytes causes oxidative stress and lipid perocidation. Tobacco smoking is also associated with reduction of Tp53, which is a tumour suppressor protein.

Heavy smoking is associated with increased carboxyhaemoglabin and decreased oxygen carry capacity of red blood cells. It happens due to present of PAH (Poly aromatic hydrocarbon). Hypoxia stimulates erythropoietin production, a hormone produced by the kidney that promotes the formation of red blood in the bone marrow, which induces hyperplasia, indicates proliferation of cells within organ or tissue, of the bone marrow. It enhances the development of secondary polycythemia, is a disorder that causes too many red blood cells are produced, and increases red blood cells abnormally. This increases catabolic iron derived from both senescent red blood cells and iron derived from increased destruction of red cells associated with polycythemia. After that erythropoietin enhances the absorption of iron from the intestine. The absorption of excess catabolic iron leads to its accumulation in macrophage and in hepatocytes over time promotes oxidative stress to the cells. Increased red cells mass with increased purine catabolism, promotes excessive production of uric acid. It increases liver cell injury and enhances liver cancer.

Hepatocellular carcinoma

Hepatocellular carcinoma is also known as primary liver cancer or hepatoma. This is the third most common cancer in the world. This cancer usually arises from liver cirrhosis, which arises due to smoking. Liver cirrhosis is a condition in which the liver slowly deteriorates and malfunctions due to chronic injury.

The carcinogens present in tobacco can cross the placenta and reaches the fetal liver cells causing hepatocellular carcinoma. The alpha-fetoprotein (AFP) is synthesized by immature liver cells in the fetus and its concentration decreases after the one tear of birth. The unusual high concentration of the protein is associated with the development of hepatocellular carcinoma. Thus, this protein acts as a biomarker to estimate the birth defects.

Fig.2. Hepatocellular carcinoma

Genetic level understanding

TABLE

GENES

FUNCTION

MUTATION

POSITION

IL-1

IL-1 proteins are involved in the inflammatory

response, being identified as endogenous pyrogens, and are reported to stimulate the release of prostaglandin and

collagenase from synovial cells.

IL-1beta TaqI and IL-1Ra gene polymorphisms

Chr 2 q13

IL-6

This gene encodes a cytokine that functions in inflammation and the maturation of B cells. The protein is primarily produced at sites of acute and chronic inflammation, where it is secreted into the serum and induces a transcriptional

inflammatory response through interleukin 6 receptor, alpha.

G 174 C

Chr 7 p15.3

TNF-α

This gene encodes a multifunctional proinflammatory cytokine that belongs to the tumour necrosis factor (TNF)

Superfamily. This cytokine is mainly secreted by macrophages. It can bind to, and thus functions through its receptors

TNFRSF1A/TNFR1 and TNFRSF1B/TNFBR. This cytokine is involved in the regulation of a wide spectrum of biological

processes including cell proliferation, differentiation, apoptosis, lipid metabolism, and coagulation

G308 A

Chr 6 p21.31

1GF2R

Transport of phosphorylated lysosomal enzymes from the Golgi complex and the cell surface to lysosomes

Chr 6q26

GSST1 (deletion polymorphism)

proteins that catalyze the conjugation of reduced glutathione to a variety of electrophilic and hydrophobic compounds

Chr 22q11.23

GSTM1

functions in the detoxification of electrophilic compounds, including carcinogens,therapeutic drugs, environmental toxins and products of oxidative stress, by conjugation with glutathione

null phenotype

Chr 1p13.3

TP53

This gene encodes tumour protein P53, which responds to diverse cellular stresses to regulate target genes that induce cell cycle arrest, apoptosis, senescence, DNA repair, or changes in metabolism.

G 249 T

Chr 17 p13.1

CYP1A1

encodes cytochrome P450 proteins which catalyze reactions like drug metabolism and synthesis of cholestrol

Ile-Val

Chr 15q24.1

Reference

Zayadi: Heavy smoking and liver. World Journal of Gastroenterology. 12(38). pp (6098-6101). 2006.

http://www.informaworld.com/smpp/content~db=all~content=a912048369

http://www.ncbi.nlm.nih.gov/pubmed/10848780

http://ehp.niehs.nih.gov/members/1997/105-4/lasky-full.html

Writing Services

Essay Writing
Service

Find out how the very best essay writing service can help you accomplish more and achieve higher marks today.

Assignment Writing Service

From complicated assignments to tricky tasks, our experts can tackle virtually any question thrown at them.

Dissertation Writing Service

A dissertation (also known as a thesis or research project) is probably the most important piece of work for any student! From full dissertations to individual chapters, we’re on hand to support you.

Coursework Writing Service

Our expert qualified writers can help you get your coursework right first time, every time.

Dissertation Proposal Service

The first step to completing a dissertation is to create a proposal that talks about what you wish to do. Our experts can design suitable methodologies - perfect to help you get started with a dissertation.

Report Writing
Service

Reports for any audience. Perfectly structured, professionally written, and tailored to suit your exact requirements.

Essay Skeleton Answer Service

If you’re just looking for some help to get started on an essay, our outline service provides you with a perfect essay plan.

Marking & Proofreading Service

Not sure if your work is hitting the mark? Struggling to get feedback from your lecturer? Our premium marking service was created just for you - get the feedback you deserve now.

Exam Revision
Service

Exams can be one of the most stressful experiences you’ll ever have! Revision is key, and we’re here to help. With custom created revision notes and exam answers, you’ll never feel underprepared again.