1) Action potentials are electrical signals that propagate along excitable cell membranes and are initiated by stimuli. They involve the movement of ions through voltage-gated ion channels.
2) In neurons, an action potential is a brief reversal of the membrane potential followed by repolarization. This allows communication over long distances.
3) Cardiac action potentials have a depolarizing phase, plateau phase, and repolarizing phase due to calcium ion involvement. This allows for sustained contraction of heart muscle.
The nervous system is a complex collection of nerves and specialized cells known as neurons that transmit signals between different parts of the body. The presentation provides a simplified overview of the nervous system and its functions
This presentation focuses on detail of the contraction of the contractile fibers in the muscles. short introduction to the ion channels, different potentials and phases working on the contraction of the muscles.
Reference: Anatomy, Physiology & Pathophysiology by Gerard J. Tortora
The nervous system is a complex collection of nerves and specialized cells known as neurons that transmit signals between different parts of the body. The presentation provides a simplified overview of the nervous system and its functions
This presentation focuses on detail of the contraction of the contractile fibers in the muscles. short introduction to the ion channels, different potentials and phases working on the contraction of the muscles.
Reference: Anatomy, Physiology & Pathophysiology by Gerard J. Tortora
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
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
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Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
- 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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Title: Sense of Taste
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 structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
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micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
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NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
2. All cells for example muscle cells , neuron cells
( nerve cells ) and cardiac cells posses electrical
excitability, the ability to response to a stimulus and
convert it into an action potential
Stimulus :- Any change in the environment that is
strong enough to initiate an action potential , for
e.g. sound & pressure wave etc.
3. Action potential :- An electrical signal that propagates
along the surface of the membrane of a neuron
(nerve cell ) due to the movement of ions ( sodium &
potassium) between interstitial fluid and the inside of a
neuron through specific ion channels in its plasma
membrane
4. ELECTRIC SIGNAL
Two types
Graded potential :- short distance communication (e.g. mainly in the
dendrites and cell body of a neuron)
Action potential :- communication over long distance within the
body
Graded potential :- on the basis of site of stimulus
Post synaptic potential :- dendrites or cell body of a neuron in
response to a neurotransmitter .
Receptors & generator potential :- sensory receptors
and sensory neurons .
5.
6. The production of these types of potential depends
on few basic features of the plasma membrane of
excitable cells
a) Existence of membrane potential
b) Presence Of specific types of ion channels
7. MEMBRANE POTENTIAL
An electrical potential difference across the
membrane
It is like voltage stored in battery
In living cells the flow of ions rather than electrons
constitutes the electrical current/ signal
Because the lipid bilayer of the plasma membrane
is a good electrical insulator . The main path for
current to flow across the membrane are through
ion channels.
8. ION CHANNELS
Ion channels open and close due to presence of
gates ( gate is a part of channel protein that can
seal the channel, pore shut or move aside to open
the pore)
When ion channels are opened, they allow specific
ions to move across the plasma membrane, down
their electrochemical gradient.
As ions move , they create a flow of electrical
current that can charge the membrane potential
9.
10. The electrical signal produced by nerve and muscle fiber rely on
four types of ion channels
a) Leakage channel :- randomly open and close
b) Ligand - gated channel :- open in response to the binding of a
ligand (chemical) stimulus
c) Mechanical- gated channel :- mechanical stimulus ( touch,
press ,vibration, tissue stretching )
d) Voltage- gated channel:- voltage stimulus
11. RESTING MEMBRANE POTENTIAL (RMP)
RMP exists because of a small build of negative
ions in the cytosol along the inside of the
membrane and an equal build up of positive ions is
the extra-cellular fluid (ECF)
Such separation of positive and negative electrical
charges is a form of potential energy which is
measured in volts or millivolts.
12. In neurons the RMP ranges from -40 to -90 mv ( typically
-70mv). here negative sign indicates that the inside the cell
is negative relative to the outside.
A cell that exhibits a membrane potential is said to be
polarized.
Resting membrane potential arises from three major factors.
1. Unequal distribution of ions in the ECF and cytosol.
ECF is rich in sodium and chloride ions
Cytosol - potassium , phosphate and amino acids
13. Because the plasma membrane typically has
more potassium leakage channels than sodium
leakage channel , the numbers of potassium
ions that diffuse down their concentration
gradient out of the cell into the ECF in greater
than the number of sodium ions that diffuse
down their concentration gradient from the ECF
into the cells.
14. As more and more positive potassium ions exit , the inside of
the membrane becomes increasingly negative and the
outside of the membrane becomes increasingly positive.
2. Inability of most anions to leave the cell
some anions cannot follow potassium out of the cell
because they are attached to non – diffusible molecules
such as ATP and large proteins.
15. 3. ELECTRO GENIC NATURE OF THE
SODIUM/POTASSIUM ATPASE
SODIUM – POTASSIUM PUMP
Small inward sodium leak and outward potassium leak are offset
by the sodium/potassium ATPase ( sodium – potassium pump )
Uneven distribution of sodium and potassium channel if
(sodium channel increase then more positivity inside the cell )
Pumps out sodium ions as fast as it leaks in and at the same
time , the sodium –potassium ATPase bring in K+ .
Na+/K+ ATPase expel 3 Na+ for each 2 K+ imported.
These pumps remove more positive charges from the cell than
they bring into the cell , they are electro genic , which means they
contribute to the negativity of the resting membrane potential .
17. GENERATION OF ACTION POTENTIAL
Action potential / impulse is a sequence of rapidly
occurring events that decreases and reverse the
membrane potential and then eventually restore it to the
resting state .
Two main phase
1. Depolarizing phase
2. Repolarizing phase
19. ALL OR NONE PRINCIPLE
.
Supra – threshold And sub - threshold stimulus doesn't cause
an action potential because it does not bring the membrane
potential to the threshold .
Threshold stimulus is just enough to depolarize the stimulus
is strong enough to depolarize the membrane above threshold .
Action potential either occurs completely or it doesn't
occur at all.
20.
21. 1. DEPOLARIZING PHASE
Negative membrane potential becomes less negative
, reaches to zero and then positive .
Stimulus – membrane of the axon to depolarize to
threshold ( -55mV ) , voltage gated Na+ channel open
rapidly .
Inward movement of Na+ changes the membrane potential
from -55mV to +30mV.
22.
23. Voltage gated Na+ channel
1. Resting state :- inactivation gate is open , but the
activation gate is closed.
2. Threshold state :- both activation and inactivation gate
are open .
As more channels open , Na+ inflow increases , the
membrane depolarizes further and more Na+ channel open
– positive feedback mechanism .
24.
25. 2. REPOLARIZING PHASE
K+ channels are opening , accelerating K+ outflow , slowing of
Na+ inflow and acceleration of K+ outflow causes the
membrane potential to change from +30mV to -70mV .
26.
27.
28. AFTER – HYPERPOLARIZING PHASE
Voltage gated K+ channels open
Membrane potential becomes even more negative ( -
90mV )
As the voltage gated k+ channel close , the membrane
potential returns to the resting level of
-70mV .
29. REFRACTORY PERIOD
The period of time after an action potential begins during which
an excitable cell cannot generate another action potential in
response to a normal threshold stimulus .
During the absolute refractory period , even a very strong
potential cannot initiate second action potential .
During the relative refractory period second action potential
can be initiated , but only by a larger than normal stimulus .
31. Because an action potential travels from point to point along
the membrane without getting smaller, it is useful for long-
distance communication.
Nerve impulse propagation in which the impulse “leaps” from
one node of Ranvier to the next along a myelinated axon is
saltatory conduction. Saltatory conduction is faster than
continuous conduction.
Axons with larger diameters conduct impulses at higher
speeds than do axons with smaller diameters.
The intensity of a stimulus is encoded in the frequency of action
potentials and in the number of sensory neurons that are
recruited.
32. CARDIAC ACTION POTENTIAL
The action potential initiated by the SA node travels along the
conduction system and spreads out to excite the “working” atrial
and ventricular muscle fibers, called contractile fibers.
An action potential occurs in a contractile fiber by :-
1. Depolarizing phase
2. Plateau phase
3. Repolarizing phase
33. 1. DEPOLARIZING PHASE
When a contractile fiber is brought to threshold by an action potential
from neighboring fibers, its voltage gated fast Na channels open.
Opening of these channels allows Na inflow because the cytosol of
contractile fibers is electrically more negative than interstitial fluid and
Na concentration is higher in interstitial fluid.
Inflow of Na down the electrochemical gradient
produces a rapid depolarization.
Within a few milliseconds, the fast Na channels automatically
inactivate and Na inflow decreases.
34. 2. PLATEAU PHASE
a period of maintained depolarization.
It is due in part to opening of voltage-gated slow Ca2 channels
in the sarcolemma.
When these channels open, calcium ions move from the
interstitial fluid (which has a higher Ca2 concentration) into the
cytosol. This inflow of Ca2 causes even more Ca2 to pour out of
the sarcoplasmic reticulum into the cytosol through additional
Ca2 channels in the sarcoplasmic reticulum membrane. The
increased Ca2 concentration in the cytosol ultimately triggers
contraction.
35. voltage-gated K channels are also found in the sarcolemma
of a contractile fiber.
Just before the plateau phase begins, some of these K
channels open, allowing potassium ions to leave the contractile
fiber.
Therefore, depolarization is sustained during the plateau phase
because Ca2 inflow just balances K outflow.
36. 3. REPOLARIZING PHASE
After a delay (which is particularly prolonged in cardiac muscle),
additional voltage-gated K channels open. Outflow of K restores
the negative resting membrane potential (90 mV).
At the same time, the calcium channels in the sarcolemma and
the sarcoplasmic reticulum are closing, which also contributes
to repolarization.
37. The mechanism of contraction is similar in
cardiac and skeletal muscle ,
Propagation of a muscle action potential along the sarcolemma
& into the T-tubule system initiates the events of muscle
contraction.
The electrical activity (action potential) leads to the mechanical
response (contraction) after a short delay.
38. As Ca2 concentration rises inside a contractile fiber, Ca2 binds to
the regulatory protein troponin, which allows the actin and
myosin filaments to begin sliding past one another, and tension
starts to develop.
Substances that alter the movement of Ca2 through slow Ca2
channels influence the strength of heart contractions.
Epinephrine, for example, increases contraction force by
enhancing Ca2 flow into the cytosol.
39. The refractory period of a cardiac muscle fiber lasts longer than
the contraction itself . As a result, another contraction cannot
begin until relaxation is well underway.
For this reason, tetanus (maintained contraction) cannot occur
in cardiac muscle as it can in skeletal muscle.
ventricles pumping function depends on alternating contraction
(when they eject blood) and relaxation (when they refill).
If heart muscle could undergo tetanus, blood flow would cease.