paraphrase the below in your own biological (Physiological) words and change it in a way that it means the same but in different words and arrangement.
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The hepatic Portal system is a unique system that contains a unique pattern of capillaries then veins then capillaries then veins. It is responsible for delivering products of digestion in the small intestines in to the liver through the hepatic portal vein. The blood from small intestine rich in products of digestion then flows through liver capillaries (sinusoids) after which the blood leaves via the hepatic vein to join regular venous circulation and drains into the inferior vena cava.
Role of hepatocytes include;
· After a meal, the hepatocytes absorb from the blood – glucose, amino acids, iron, vitamins, and other nutrients for metabolism or storage after a meal.
· Between meals, hepatocytes break down stored glycogen and release glucose into the blood
· Remove and degrade: hormones, toxins, bile pigments, and drugs
· Secrete into the blood: albumin, lipoproteins, clotting factors, angiotensinogen, and other products
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1- Parasympathetic division (extrinsic regulation)
– Stimulates esophagus, stomach, small intestine, pancreas, gallbladder, and first part of large intestine via Vagus nerve
– Spinal nerves in sacral region stimulate lower large intestine.
– Parasympathetic neurons synapse on submucosal and myenteric plexuses.
2- Sympathetic division (extrinsic regulation)
– Inhibits peristalsis and secretion
– Stimulates contraction of sphincters
3- Hormones – from brain or other digestive organs e.g. gastrin and secretin
4- Intrinsic regulation
– Intrinsic sensory neurons in gut wall help in intrinsic regulation via separate enteric nervous system
5- Paracrine signals : secretions from specialized cells in the GI tract that induce changes in the nearby cells
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Stomach is protected from the harsh acidic and enzymatic environment it creates by:
– Mucous coat: thick, highly alkaline mucus resists action of acid and enzymes
– Tight junctions between epithelial cells prevent gastric juice from seeping between them and digesting deeper tissue
– Epithelial cell replacement: cells live only 3 to 6 days, sloughed off into chyme
Replaced rapidly by cell division in gastric pits
Breakdown of these protective measures can result in inflammation (gastritis) and peptic ulcer
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- Mucous cells—secrete mucus
- Also called mucous neck cells since they are concentrated at the neck of the gland.
- Parietal cells—found mostly in the lower half of the gland
- Secrete hydrochloric acid (HCl), intrinsic factor, and a hunger hormone called ghrelin
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