Topic Concentration Guide for Chapter 22, 23, & 24 (A&P 2 Lecture) Functions of the Liver

Synthesizes what 6 things?

1.) Synthesizes bile, which is used for emulsification of fats in the small intestine

2.) Synthesizes angiotensinogen. This inactive hormone is continually synthesized and pushed to the blood. It’s conversion to Angiotensin 1 is the first step in the RAAS system, whose mechanisms elevate

3.) Synthesizes non-essential amino: The 8-9 essential amino acids must be obtained from the diet, and the liver is able to use some of these to synthesize non-essential amino acids, so that proteins such as fibrinogen and albumin can be made in the liver.

4.) Synthesizes cholesterol molecules that are part of cell membranes and steroid based hormones, such as testosterone and aldosterone.

5.) Synthesizes lipoproteins (the dietary cholesterols HDL, LDL, and VLDL) that are used to transport lipids around the body.

6.) Synthesizes some plasma proteins including albumin (the most abundant plasma protein), fibrinogen, and alpha-globulins and beta-globulins used in the production of hemoglobin.

Performs lipogenesis

a process in which insulin causes excess glucose, fatty acids, and amino acids to be formed into triglycerides. These are stored in adipose tissue.

Performs gluconeogenesis

a process in which new glucose molecules are synthesized from pyruvate, lactate, glycerol, or the amino acids alanine or glutamine. This process can be initiated by several hormones including epinephrine, cortisol, glucagon, and growth hormone.

Performs glycogenolysis

a process in which glucagon stimulates the breakdown of glycogen molecules to glucose.

Performs glycogenesis

a process in which insulin stimulates the formation of glycogen molecules from glucose. CoA, which can be further modified and used in the mitochondria to produce ATP.

Performs ketogenesis

In this process, acetyl CoA molecules are converted into ketone-based chemicals (ketone bodies), which can be used by the brain to make ATP in times of extreme carbohydrate deficit or ample lipid availability. Human bodies make a small number of ketones regularly. Ketoacidosis, a dangerous condition in which blood becomes abnormally acidic, can occur when too many ketone bodies are produced, as may be seen in uncontrolled diabetes mellitus.

Stores several vitamins include vitamins

D, A, K, and B12

Stores what two things?

glycogen and triglycerides, which can be used to synthesize ATP

Performs β-oxidation

(beta oxidation) of fatty acids. In this process, fatty acids are converted to acetylCoA, which can be further modified and used in the mitochondria to produce ATP.

Forms urea to be excreted by the kidneys.

High levels of ammonia, a breakdown product of protein metabolism, are toxic to the body. To prevent toxicity, the liver forms urea and water by combining ammonia (NH3) + CO2

Filters what?

blood, blood entering the liver from the hepatic portal system moves through the portal venules, which are inhabited by stellate macrophages. These macrophages phagocytize antigens and serve as antigen presenting cells for the adaptive immune system

Metabolizes what?

drugs, medications, and alcohol into inactive products to be excreted by kidneys