What features of a liver cell show it is metabolically active?
Liver cells, also known as hepatocytes, exhibit several features that indicate their high metabolic activity. Here are some key characteristics:
1. Mitochondria: Liver cells contain numerous mitochondria, which are the primary sites for energy production through oxidative phosphorylation. The abundance of mitochondria reflects the high energy demand of liver cells for various metabolic processes.
2. Endoplasmic Reticulum (ER): The liver cells have a well-developed endoplasmic reticulum, both rough ER (studded with ribosomes) and smooth ER. The rough ER is involved in protein synthesis, including the production of enzymes and plasma proteins, while the smooth ER plays a crucial role in lipid metabolism, detoxification reactions, and calcium storage.
3. Lysosomes: Liver cells contain numerous lysosomes, which are membrane-bound organelles responsible for intracellular digestion and recycling. They help in the degradation of damaged organelles, phagocytosis, and detoxification processes.
4. Glycogen Storage: Liver cells function as a primary storage site for glycogen, a branched polymer of glucose. Glycogen is synthesized from glucose when blood sugar levels are high and broken down to release glucose when blood sugar levels drop, helping maintain glucose homeostasis in the body.
5. Detoxification Enzymes: Liver cells contain various enzymes that play a crucial role in detoxification processes. They detoxify harmful substances such as drugs, toxins, and metabolic waste products, converting them into less harmful or excretable forms.
6. Bile Production: Liver cells produce bile, a greenish-yellow fluid that aids in the digestion and absorption of fats. Bile is composed of bile salts, phospholipids, cholesterol, and other components. It is stored in the gallbladder and released into the small intestine when needed.
7. Protein Synthesis: Liver cells are responsible for the synthesis of various proteins, including albumin, clotting factors, lipoproteins, and enzymes essential for metabolism. Albumin helps maintain osmotic balance in the blood, while clotting factors are necessary for blood coagulation. Lipoproteins transport lipids throughout the body, and enzymes facilitate numerous biochemical reactions.
These features collectively demonstrate the metabolically active nature of liver cells, enabling them to carry out diverse functions crucial for maintaining overall body homeostasis and metabolism.