GIT Physiology: A Detailed Concept .....

This document presents the physiology of a human stomach. This overview covers the main aspects of GIT physiology. Each component plays a crucial role in the digestion, absorption, and elimination processes essential for nutrition and overall health.

1. Physiology of GIT Kartik Mittal 212089050018 B.Pharm III Year M.J.P. Rohilkhand University, Bareilly

2. Contents at a Glance Overview Processing of Food Properties of GI Muscles Enteric Nervous System Secretory Products of Gastric Mucosal Glands Satiety Chewing & Swallowing Salivary Secretions Gastric Secretions Digestion & Absorption Defecation 20/11/2022 ‹#› Kartik Mittal

3. Overview GIT is important for digestion and absorption of food. As food is broken down into small absorbable particles that is ultimately used up by cell for production of energy and essential life processes. GI tract or alimentary canal, a continuous tube start from mouth and end at anus. Organs of GIT - mouth, pharynx, esophagus, stomach, small intestine and large intestine. Accessory digestive organs are teeth, tongue, salivary glands, liver, gall bladder and pancreas. ‹#›

4. Processing of Food INGESTION → MECHANICAL DIGESTION→ PROPULSION → SECRETIONS → DIGESTION → ABSORPTION → ELIMINATION. ■ Teeth reduces size of food, increase surface area fo absorption. ■ Tongue aid in movement, mixing and swallowing of food. ■ Motility, the ability of GIT to mix and move material along its length. ‹#›

5. Properties of GI Muscles Undergo mus cle contraction due to electrical signal transmission b/w consecutive muscle fibres. Electrical waves that contribute to membrane potential- Slow Waves :- Initiated and propagated by cajal cells, don't cause contraction only activate L type Ca 2+ channels causing its influx and initiation of motility. Spikes :- True A.P., RMP reach -40mV or more. Regulated by ANS, GI hormones. ‹#›

6. En teric Nervous System Indigenous nervous system of GIT, part or ANS. Receptors – ▪︎ Chemo receptor:- respond to chemicals of food. ▪︎ Stretch receptor:- respond to food swollen. Plexus – ▪ Submucosal Nerve Plexus (mesissner’s):- innervate secretory cells controlling digestive secretions. ︎ ▪ Myenteric Nerve Plexus:- innervate smooth muscle cells controlling the GI motility.︎ ‹#›

7. Enteric Nervous System Extrinsic Branches of GI innervation : – PSNS Innervation Incre ase the contraction of GIT via cranial nerve X with the aid of ACh. Vagus nerve innervate upper GIT, esophagus, stomach, small intestine, ascending and proximal transverse colon. Pelvic nerve innervate lower GIT, distal transverse colon and descending sigmoid colon. Carry out action via ACh or VIP. ‹#›

8. Enteric Nervous System 2. SNS Innervation: – Sympathetic preganglionic neurons are cholinergic while postganglionic n eurons are adrenergic and secrete noradrenaline. Via celiac or superior mesenteric ganglia it decreases the contractions of GIT. ‹#›

9. ANS Innervation ‹#›