This document discusses gastrointestinal physiology, specifically focusing on the musculature of the digestive tract. It describes the main muscle layers - longitudinal and circular muscles - and how their contractions function to move food through the tract. It also discusses the electrical activity of the muscles, including slow waves and spike potentials generated by interstitial cells of Cajal that control the rhythm of movements. Contractions can be either phasic with relaxation, seen in most of the tract, or tonic without relaxation, as in sphincters.
Receptor by Pandian M, Tutor, Dept of Physiology, DYPMCKOP, MH. This PPT for ...Pandian M
Introduction
SENSORY RECEPTORS
Structurally 3 types of receptors
Transducers
CLASSIFICATION OF RECEPTORS
A. Depending on the source of stimulus(Sherrington’s classification)
B. Depending upon type of stimulus
C. Clinical or anatomical classification of receptors
Production of receptor potential
Properties of receptors
Properties of receptor potential
Receptor by Pandian M, Tutor, Dept of Physiology, DYPMCKOP, MH. This PPT for ...Pandian M
Introduction
SENSORY RECEPTORS
Structurally 3 types of receptors
Transducers
CLASSIFICATION OF RECEPTORS
A. Depending on the source of stimulus(Sherrington’s classification)
B. Depending upon type of stimulus
C. Clinical or anatomical classification of receptors
Production of receptor potential
Properties of receptors
Properties of receptor potential
PHYSIOLOGY OF THE GASTROINTESTINAL TRACT (GIT)
Main function: The GIT provides the body with a supply of water, nutrients, electrolytes,
vitamines.
Actions:
1) Digestion of the food
2) Absorption of the products of digestion
Ad 1) Digestive processes: - mechanical
- chemical
Mechanical methods: - mastication (chewing)
- swallowing (deglutition)
- movements of the GIT
(motor functions)
Chemical means (secretions): - saliva
- gastric juice
- pancreatic juice
- intestinal juice
- bile
PHYSIOLOGY OF MOUTH
Functions:
1/ Mechanical and chemical digestion of the food
2/ The source of the unconditioned reflexes
3/ Control of physical and chemical properties of the food
Ad 1 a Mechanical activity – mastication
The anterior teeth – a cutting action
The posterior teeth – a grinding action
Thee maximal closing force - incissors 15 kg
- mollars 50 kg
Inervations of the muscles of chewing – 5th, 8th, 12th cranial nerves
Centers – near the brain stem and cerebral cortex centers for taste
Act of mastication:
The movement of the lower jaw down:
- Contraction of m. biventer mandibulae (m.digastricus), m.
pterygoideus ext., m.m. infrahyoidei →
The movement – up: the drop initiates a stretch reflex
Contraction of m. masseter, m. temporalis, m. pterygoideus
Rebound of antagonists- inhibition – the jaw drops +
compression of the bolus of the food against the linings of the mouth - rebound – repetitive
actions.....
Mastication reflexive and voluntary
Function of the mastication: - grinding the food
- mixing with saliva
- prevention of excoriation of GIT
- makes easy swalowing
2
- aids subsequent digestion
SALIVATION
Ad 1 b) Adjustment of the food by the saliva
The salivary glands: - parotid
- submandibular
- sublingual
- buccal
Secretion of the saliva: - basal - 800 – 1500 ml/day
- during intake of food
Regulation of salivary secretion
– nervous - parasympathetic
- sympathetic
Unconditioned reflexes:
Taste and tactile stimuli increase 8-20 times the basal rate of secretion
Conditioned reflexes:
Visual, olphactoric, acoustic stimuli
Centers: salivatory nuclei (at the juncture of the medulla and pons):
superior – submandibular (70%), sublingual (5%)
inferior – parotid (serous saliva).
The gastrointestinal system consists of the gastrointestinal tract and the accessory exocrine glands. The gastrointestinal tract includes the mouth, the esophagus, the stomach, the small intestine, and the large intestine. The major accessory glands are the salivary glands, the liver, the gallbladder, and the pancreas.
The major functions of the gastrointestinal system are assimilation of nutrients and excretion of waste products via the biliary system. Movement of food through the gastrointestinal system (motility) is carefully coordinated with the delivery of appropriate fluid and enzyme solutions (secretion) so that the macromolecules in food can be hydrolyzed (digestion) and the nutrient molecules, which are liberated, can be transported into the circulatory.
Medical Physiology of the GIT:
Mucosa, principles of GIT function, afferent sensory innervation, GI reflexes, motility throughout the GI system, control of stomach emptying, coordination of motility, GI secretions, Gastric events following ingestion of a meal......
Glomerular Filtration rate and its determinants.pptxDr.Nusrat Tariq
The first step in urine formation is filtration of large
amounts of fluid through the glomerular capillaries into
Bowman’s capsule—almost 180 L/day. Most of this filtrate is reabsorbed, leaving only about 1 liter of fluid to be
excreted each day, although the renal fluid excretion rate
is highly variable, depending on fluid intake. The high rate
of glomerular filtration depends on a high rate of kidney
blood flow, as well as the special properties of the glomerular capillary membranes.
Glomerular Filtration and determinants of glomerular filtration .pptxDr.Nusrat Tariq
The first step in urine formation is filtration of large
amounts of fluid through the glomerular capillaries into
Bowman’s capsule—almost 180 L/day. Most of this filtrate is reabsorbed, leaving only about 1 liter of fluid to be
excreted each day, although the renal fluid excretion rate
is highly variable, depending on fluid intake. The high rate
of glomerular filtration depends on a high rate of kidney
blood flow, as well as the special properties of the glomerular capillary membranes.
this lecture gives detailed account of functions of liver as an organ, secretion, regulation and functions of biliary secretion. exocrine and endocrine functions of pancreas. composition of pancreatic secretions
Diffusion potential. Large Nerve. Na -K ATPase. Guyton and Hall. Medical Physiology. Dr. Nusrat Tariq. Professor Of Physiology. M.I.M.D.C. GOLDMAN HODGKIN KATZ EQUATION
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
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Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
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2. Dr. Alzoghaibi 2
Gastrointestinal physiology:
A branch of human physiology
that addresses the physical function of
the gastrointestinal (GI) system.
3. .
Gastrointestinal system:
1-The GIT— a series of hollow organs:
Mouth
Esophagus
stomach
small intestine
large intestine— rectum and anus.
2- Solid accessory organs:
Liver
Pancreas
Gallbladder 3
4.
5. Primary Functions of Digestive System
1. Ingestion - getting food into the GI tract (eating)
2.Propulsion - moving food along the tract by swallowing and peristalsis
(wave-like motion)
3.Mechanical Digestion - the physical grinding and churning of foodstuffs to
breakdown and expose to enzymes and the surface of the GI tract
4.Chemical Digestion - breakdown of larger molecules into absorbable parts
by enzymatic action
5.Absorption - transport of digested molecules, vitamins, minerals, water, into
blood
6. Excretion - elimination of unused foodstuff, heavy metals, toxins,
alkaloids.(feces).
7. Helps Erythropoises by secreting intrinsic factor needed for Vitamin B12
absorption 5
9. The Musculature of the Digestive
Tract
Two Main Muscle Layers:
Longitudinal muscle layer
Circular muscle layer
Oblique muscle layer (stomach only)
9
10. The Musculature of the Digestive Tract
Longitudinal Muscle:
Contraction shortens the segment of the intestine and
expands the lumen
Innervated by ENS, mainly by excitatory motor neuron
Ca influx from out side is important.
Circular muscle:
Thicker and more powerful than longitudinal.
Contraction reduces the diameter of the lumen and
increases its length .
Innervated by ENS, both excitatory and inhibitory motor
neurons.
More gap junctions than in longitudinal muscle.
Intracellular release of Ca is more important
10
11. SMOOTH MUSCLE OF G.I.T
1.Unitary type,visceral or syncytial
smooth muscle.
2.Multiunit type smooth muscle.
11
12. SMOOTH MUSCLE OF G.I.T
Unitary type,visceral or syncytial smooth
muscle.
Contract spontaneously in response to
stretch in the absence of neural or hormonal
influence (such as in stomach and intestine)
Cells are electrically coupled via gap junctions
so each muscle layer functions as a
syncytium.
12
13. SMOOTH MUSCLE OF G.I.T
Multiunit type smooth muscle.
Contract in response to neural input but
not to stretch (such as in esophagus &
gall bladder).
Composed of discrete independently
working smooth muscle fibers ,each of
which is innervated by single nerve
ending.
13
16. Slow waves
They are not action potential but are slow undulating changes
in membrane potential(-56mv)
Frequency of slow waves determines rhythm of gastrointestinal
movements.
They do not cause Ca++ to enter the smooth muscles so by
themselves cause no muscle contraction.They mainly excite
the appearance of intermittent spike potentials.
Occur at different frequency
stomach (3/min)
small intestine (duodenum, 12/min)
ileum & colon (8-9/min).
16
17. .
17
Caused by complex interactions among smooth muscle
cells and specialized cells called Interstitial Cells Of
Cajal (Electrical Pacemaker).
These interstitial cells form a network with each
other and are interposed between the smooth muscle
layers, with synaptic-like contacts to smooth muscle
cells.
The interstitial cells of Cajal undergo cyclic changes in
membrane potential due to unique ion channels that
periodically open and produce inward (pacemaker)
currents that may generate slow wave activity.
19. Spike Potentials
The spike potentials are true action potentials.
They occur automatically when the resting membrane
potential of the gastrointestinal smooth muscle becomes more
positive than about −40 millivolts (the normal resting
membrane potential((−50 −60 ml.volts).
Spike potentials appear on the peaks of slow waves.
The higher the slow wave potential rises, the greater the
frequency of the spike potentials, usually ranging between 1
and 10 spikes per second.
The spike potentials last 10 to 40 times as long in
gastrointestinal muscle as the action potentials in large nerve
fibers, with each gastrointestinal spike lasting as long as 10 to
20 milliseconds.
19
21. Figure 62-3; Guyton & Hall
Each time the peaks of the
slow waves temporarily
become more positive
than -40 millivolts, spike
potentials appear on these
peaks
The higher the
slow wave
potential rises, the
greater the
frequency of the
spike potentials,
usually ranging
between 1 and 10
spikes per second.
22. .
Factors that depolarize the membrane:
Stretching of the muscle
Ach
Parasympathetic stimulation
Hormonal stimulation
Factors that hyperpolarize the membrane:
Norepinephrine
Sympathetic stimulation
22
23. Contractions in Gastrointestinal Smooth Muscles
Phasic contractions
Periodic contractions followed by relaxation; such as in gastric
antrum, small intestine and esophagus
Tonic contractions
Maintained contraction without relaxation; such as in orad
region of the stomach, lower esoghageal, ileocecal and
internal anal sphincter
Not associated with slow waves .
- Caused by:
• Continuous repetitive spike potential
• Hormonal effects
• Continuous entery of Ca ions.
23