The document discusses the circulatory system and blood pressure regulation. It describes the different types of blood vessels - arteries, arterioles, capillaries and veins. Arteries carry blood away from the heart while veins carry blood back to the heart. Capillaries are where gas and nutrient exchange occurs. Blood pressure is regulated through short-term mechanisms like the baroreceptor reflex and long-term mechanisms like the renin-angiotensin system. Heart failure and shock can occur if the heart or blood vessels are unable to effectively circulate blood and maintain adequate blood pressure.
Cardiovascular physiology. Cardiac enzymes and their effects in the body system. Cardiac output and effects increasing and decreasing it. Calculations if Ejected fraction and other cardiac parameters.
Cardiovascular physiology. Cardiac enzymes and their effects in the body system. Cardiac output and effects increasing and decreasing it. Calculations if Ejected fraction and other cardiac parameters.
This presentation gives you a brief, understandable, captivating and presentable idea on the physiology of blood pressure regulation both on hypertension and hypotension cases.
1 GNM - Anatomy unit - 4 - CVS by thirumurugan.pptxthiru murugan
By:M. Thiru murugan
Unit – IV:
Heart : Structure, functions including conduction system & cardiac cycle
Blood vessels : Types, Structure and position
Circulation of blood
Blood pressure and pulse
Heart
The circulatory system:
It consisting of blood, blood vessels, and heart.
This supplies oxygen and other nutrients,
Transports hormones
Removes unnecessary waste products.
Heart and its Structure
The heart is a muscular organ about the size of a fist,
located in mediastinum just behind and slightly left of the breastbone (sternum).
The heart pumps blood through the blood vessels (arteries and veins called the cardiovascular system).
Structure of heart:
Layers of the heart (3)
Chambers of the heart (4)
Valves of the heart (4)
Blood vessels of the heart (5)
3 layers of the heart:
Epicardium/pericardium: outer protective layer of the heart. Visceral and parietal (pericardial fluid). Protection for the heart and big vessels and prevent collapse of heart,
Myocardium: muscular middle layer wall of the heart. Responsible for keeping the heart pumping blood around the body.
Endocardium: the inner layer of the heart. Regulate blood flow through the chambers of the heart and pass the electrical impulses
Chambers of the heart:
The atria: These are the 2 upper chambers, which receive blood. RA / LA
The ventricles: These are the 2 lower chambers, which discharge blood. RV/ LV
A wall of tissue called the septum separates the left and right atria called atrial septum and the left and right ventricle called ventricular septum.
Valves in the heart:
There are four valves
Two-atrio ventricular valves: The 2 types: bicuspid (mitral) - LA & LV, and tricuspid valves - RA & RV.
Two-semilunar valves: The aortic valves and the pulmonary valve.
Major blood vessels of the heart
There are 5 major blood vessels
Pulmonary artery
Pulmonary veins
Aorta[artery]
Inferior vena cava [IVC] veins
Superior vena cava [SVC] veins
Functions of heart:
Pumping oxygenated blood to the body parts.
Pumping nutrients and other vital substances
Receiving deoxygenated blood and carrying metabolic waste products from the body
Pumping deoxygenated blood to the lungs for oxygenation.
Maintaining blood pressure.
Conduction system
The electrical conduction system that controls the heart rate.
This system generates electrical impulses and conducts them throughout the muscle of the heart, stimulating the heart to contract and pump blood.
The electrical pulses determine the order in which the chambers contract & the heart rate
Conductive system consist of:
SA Node
AV Node
Bundle of his or His Bundles – bundle of branches
( right and left)
4. Purkinje fibres
Sinoatrial node (SA) : also known as the pace maker of the heart and Located in the upper wall of the right atrium
Made up of both muscle and nervous tissue
Here the electrical impulse begins
Atrioventricular (AV) node:
located between the atria and ventricles of the heart
The electrical impulse is carried fr
BLOOD PRESSURE
BY: SAIYED FALAKAARA
ASSISTANT PROFESSOR
DEPARTMENT OF PHARMACY
SUMANDEEP VIDYAPEETH
Definition
Arterial blood pressure can be defined as the lateral pressure exerted by moving the column of blood on the walls of the arteries.
Significance
To ensure the blood flow to various organs
Plays an important role in exchange of nutrients and gases across the capillaries
Required to form urine
Required for the formation of lymph
Normal values
Normal adult range can fluctuate within a wide range and still be normal
Systolic/diastolic
100/60 – 140/80
Unit - mmHg
This presentation is a combination of different slides which I re-purposed. I included a reference of all the slides I used at the end of my presentation.
Cardivascular system
Cardiovascular system include Heart and Blood vessels
Heart:
Pumps the blood
Blood Vessels:
Carries the blood to all parts of the body.
Location
Thorax between the lungs
Pointed apex directed toward left hip
From 2nd Rib to 6th Rib
About the size of your fist
The peripheral vascular system consists of the veins and arteries not in the chest or the abdomen that in the arm, hands, legs and feet.
The peripheral arteries supply the oxygenated blood to the body.
The peripheral veins lead deoxygenated blood from the capillaries in the back to the heart.
This presentation gives you a brief, understandable, captivating and presentable idea on the physiology of blood pressure regulation both on hypertension and hypotension cases.
1 GNM - Anatomy unit - 4 - CVS by thirumurugan.pptxthiru murugan
By:M. Thiru murugan
Unit – IV:
Heart : Structure, functions including conduction system & cardiac cycle
Blood vessels : Types, Structure and position
Circulation of blood
Blood pressure and pulse
Heart
The circulatory system:
It consisting of blood, blood vessels, and heart.
This supplies oxygen and other nutrients,
Transports hormones
Removes unnecessary waste products.
Heart and its Structure
The heart is a muscular organ about the size of a fist,
located in mediastinum just behind and slightly left of the breastbone (sternum).
The heart pumps blood through the blood vessels (arteries and veins called the cardiovascular system).
Structure of heart:
Layers of the heart (3)
Chambers of the heart (4)
Valves of the heart (4)
Blood vessels of the heart (5)
3 layers of the heart:
Epicardium/pericardium: outer protective layer of the heart. Visceral and parietal (pericardial fluid). Protection for the heart and big vessels and prevent collapse of heart,
Myocardium: muscular middle layer wall of the heart. Responsible for keeping the heart pumping blood around the body.
Endocardium: the inner layer of the heart. Regulate blood flow through the chambers of the heart and pass the electrical impulses
Chambers of the heart:
The atria: These are the 2 upper chambers, which receive blood. RA / LA
The ventricles: These are the 2 lower chambers, which discharge blood. RV/ LV
A wall of tissue called the septum separates the left and right atria called atrial septum and the left and right ventricle called ventricular septum.
Valves in the heart:
There are four valves
Two-atrio ventricular valves: The 2 types: bicuspid (mitral) - LA & LV, and tricuspid valves - RA & RV.
Two-semilunar valves: The aortic valves and the pulmonary valve.
Major blood vessels of the heart
There are 5 major blood vessels
Pulmonary artery
Pulmonary veins
Aorta[artery]
Inferior vena cava [IVC] veins
Superior vena cava [SVC] veins
Functions of heart:
Pumping oxygenated blood to the body parts.
Pumping nutrients and other vital substances
Receiving deoxygenated blood and carrying metabolic waste products from the body
Pumping deoxygenated blood to the lungs for oxygenation.
Maintaining blood pressure.
Conduction system
The electrical conduction system that controls the heart rate.
This system generates electrical impulses and conducts them throughout the muscle of the heart, stimulating the heart to contract and pump blood.
The electrical pulses determine the order in which the chambers contract & the heart rate
Conductive system consist of:
SA Node
AV Node
Bundle of his or His Bundles – bundle of branches
( right and left)
4. Purkinje fibres
Sinoatrial node (SA) : also known as the pace maker of the heart and Located in the upper wall of the right atrium
Made up of both muscle and nervous tissue
Here the electrical impulse begins
Atrioventricular (AV) node:
located between the atria and ventricles of the heart
The electrical impulse is carried fr
BLOOD PRESSURE
BY: SAIYED FALAKAARA
ASSISTANT PROFESSOR
DEPARTMENT OF PHARMACY
SUMANDEEP VIDYAPEETH
Definition
Arterial blood pressure can be defined as the lateral pressure exerted by moving the column of blood on the walls of the arteries.
Significance
To ensure the blood flow to various organs
Plays an important role in exchange of nutrients and gases across the capillaries
Required to form urine
Required for the formation of lymph
Normal values
Normal adult range can fluctuate within a wide range and still be normal
Systolic/diastolic
100/60 – 140/80
Unit - mmHg
This presentation is a combination of different slides which I re-purposed. I included a reference of all the slides I used at the end of my presentation.
Cardivascular system
Cardiovascular system include Heart and Blood vessels
Heart:
Pumps the blood
Blood Vessels:
Carries the blood to all parts of the body.
Location
Thorax between the lungs
Pointed apex directed toward left hip
From 2nd Rib to 6th Rib
About the size of your fist
The peripheral vascular system consists of the veins and arteries not in the chest or the abdomen that in the arm, hands, legs and feet.
The peripheral arteries supply the oxygenated blood to the body.
The peripheral veins lead deoxygenated blood from the capillaries in the back to the heart.
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
2. INTRODUCTION
• Blood is transported to all parts of the body through a system of
vessels that brings fresh supplies to cells and removes their
wastes
• All blood pumped by the right side of the heart passes through
the pulmonary circulation to the lungs for O2 pickup and CO2
removal.
• The blood pumped by the left side of the heart into the systemic
circulation is distributed to the systemic organs .
3.
4. • The systemic and pulmonary circulations each consist of a
continuum of different blood vessel types that begins and ends with
the heart, as follows:
• Arteries which carry blood from the heart to the organs, branch into
a “tree” of progressively smaller vessels.
• When a small artery reaches the organ it is supplying, it branches
into numerous arteriol
• Arterioles branch further within the organs into capillaries across
which all exchanges are made with surrounding cells.
5. • Capillary exchange is the entire purpose of the circulatory system
• Capillaries rejoin to form small venules, which further merge to
form small veins that leave the organs.
• The small veins progressively unite to form larger veins that
eventually empty into the heart
6.
7. ARTERIES
1- Serve as rapid passage ways for blood from the heart to the organs
2- Act as a pressure reservoir to provide the driving force for blood
when the heart is relaxing.
• The heart alternately contracts to pump blood into the arteries and
then relaxes to refill from the veins.
• As the heart pumps blood into the arteries during ventricular
systole, a greater volume of blood enters the arteries from the heart
than leaves them to flow into smaller vessels downstream
8. • The highly elastic arteries expand to temporarily hold this excess
volume of ejected blood.
• When the heart relaxes and temporarily stops pumping blood into
the arteries, the stretched arterial walls passively recoil, like an
inflated balloon that is released.
• This recoil pushes the excess blood contained in the arteries into
the vessels downstream, ensuring continued blood flow to the
organs when the heart is relaxing and not pumping blood into the
system
9. ARTERIOLES
• Arterioles are the major resistance vessels in the vascular tree
because their radius is small enough to offer considerable
resistance to flow.
• The radius (and, accordingly, the resistances) of arterioles
supplying individual organs can be adjusted independently to :
(1) variably distribute the cardiac output among the systemic
organs, depending on the body’s momentary needs
(2) help regulate arterial blood pressure
10. CAPILLARIES,
• the sites for exchange of materials between blood and tissue cells
• branch extensively to bring blood within the reach of every cell
• Materials are exchanged across capillary walls mainly by diffusion
11. VEINS
• Their walls are relatively thin and easily distended. Therefore
they can accommodate large volume of blood (capacitance
vessels)
12. BLOOD PRESSURE
• It is the force exerted by the blood against a vessel wall.
Systolic pressure
• The maximum pressure in a vessel during systole of the heart.
• Normal value is less than 120 mmHg in adults.
• Systolic blood pressure of 140 mmHg or more is hypertension.
13. Diastolic pressure
• The minimum pressure in a vessel during diastole of the heart.
• Normal value is less than 80 mmHg in adults.
• Diastolic blood pressure of 90 mmHg or more is hypertension.
Pulse pressure
• The difference between the systolic and the diastolic pressures.
• Normal pulse pressure is less than 60 mmHg.
14. Mean arterial pressure
• The mean pressure during the cardiac cycle.
• It is calculated as follows:
• The mean arterial pressure= The diastolic + 1/3 pulse pressure
15. CONTROL OF THE ARTERIAL BLOOD PRESSURE
• Blood pressure = Cardiac output × Peripheral resistance.
• The blood pressure is controlled by controlling the cardiac output
and the peripheral resistance.
• The cardiac output is controlled by controlling both the heart rate
and the stroke volume
• It determines the systolic pressure (i.e. the increase in COP increases
systolic pressure).
16. • The peripheral resistance is determined by blood viscosity, length
of arteries and radius of arteries as follows:
PR = 8VL/π 𝒓𝟒
• Where :
oV is the blood viscosity
oL is the length of arteries
o r is the radius of blood vessels.
• The peripheral resistance determines the diastolic blood pressure.
17. • Viscosity of the blood depends on:
o The packed cell volume (PCV)
o Plasma proteins especially globulins and fibrinogen
o Body temperature (constant in the physiological conditions)
• Radius of blood vessels is the most important factor in
determining the peripheral resistance
• It is inversely proportional with the peripheral resistance
18. The mechanisms that control the blood pressure
• Mean arterial pressure is constantly monitored by baroreceptors
(pressure sensors) within the circulatory system.
• When deviations from normal are detected, multiple reflex responses
are initiated to return mean arterial pressure to its normal value.
1- Short term mechanisms (act in seconds)
• Cause alterations in cardiac output and total peripheral resistance,
mediated by means of autonomic nervous system influences on the
heart, veins, and arterioles
19. 2- Long-term mechanisms (requiring minutes to days)
• involves adjusting total blood volume by restoring normal salt
and water balance through mechanisms that regulate urine
output and thirst
• The size of the total blood volume, in turn, has a profound effect
on cardiac output and mean arterial pressure
3- Local regulation of blood pressure
20. SHORT TERM MECHANISMS
• Any change in mean arterial pressure triggers an autonomically
mediated baroreceptor reflex that influences the heart and blood
vessels to adjust cardiac output and total peripheral resistance in an
attempt to restore blood pressure to normal.
• The most important receptors involved in the moment-to-moment
regulation of blood pressure, the carotid sinus and aortic arch
baroreceptors
• They are mechanoreceptors stimulated by stretch caused by high
blood pressure.
21. • They constantly provide information about mean arterial
pressure (in form of action potentials).
• They send impulses through the vagus & glossopharyngeal
nerves to cardiovascular control centers in medulla oblongata.
• The cardiovascular control center alters the ratio between
sympathetic and parasympathetic activity to the effector organ
• The efferent pathway is the autonomic nervous system.
22. • If the arterial pressure increase, the carotid sinus and aortic arch
baroreceptors increase the rate of firing.
• The cardiovascular control center responds by decreasing
sympathetic and increasing parasympathetic activity to the
cardiovascular system.
• These decrease heart rate, decrease stroke volume, and produce
arteriolar and venous vasodilation, which in turn lead to a
decrease in cardiac output and a decrease in total peripheral
resistance, with a subsequent fall in blood pressure back toward
normal
• The opposite occurs when there is reduction in B.P
23. • Chemoreceptors
- The peripheral chemoreceptors are found in the carotid body in
carotid bifurcation and aortic body in aortic arch.
- They are stimulated by hypoxia (low O2 in tissues), hypercapnia (high
CO2) and acidosis (high H + ).
These stimuli are associated with hypotension because of the low
tissue perfusion.
- They send excitatory impulses through the vagus and
glossopharyngeal nerves to the respiratory center to increase
respiration.
24. - The impulses also stimulate the vasomotor and the cardiac
centers (due to radiation of impulses in the medulla).
- This increases the blood pressure by increasing sympathetic
discharge from these centers to the heart and blood vessels
causing increased heart rate, higher stroke volume and
vasoconstriction.
25. LONG TERM MECHANISMS
Renin-Angiotensin Aldosterone system
• Renin enzyme is released by the kidney lead to formation of Angiotensin
II through many steps cascade.
• It is stimulated by renal ischemia, hyponatremia & sympathetic
stimulation (all these are associated with hypotension).
• Angiotensin II rapidly elevates the blood pressure by causing
vasoconstriction.
• In addition it has other long term effects include stimulation of
aldosterone, stimulation of ADH and stimulation of the thirst center..
26. • Aldosterone Acts on the distal convoluted tubules and collecting
ducts in kidney causing reabsorption of sodium and secretion of
potassium. Water follows sodium to the intravascular space.
• This increases blood volume & therefore the blood pressure
27. Hormonal vasoconstriction
1- anti diuretic hormone (ADH)
• Release from the posterior pituitary gland is stimulated by hypotension.
• It elevate blood pressure by:
- acts on receptors in the blood vessels causing vasoconstriction.
- Acts on receptors in the kidney causing reabsorption of water to the
intravascular space (increases blood volume )
28. 2- Catecholamines
• Adrenaline and noradrenaline are released in response to
hypotension (which is a form of stress).
• They act on receptors in blood vessels causing vasoconstriction.
This elevates the blood pressure.
29. LOCAL REGULATION
• Aim of Local regulation of blood pressure:
o To maintain adequate perfusion and therefore adequate supply of O2
and nutrients to the tissues.
o To adjust the perfusion to tissues according to their needs; which vary
from time to time according to variation in activities.
• Local regulation occurs by the following:
1- Autoregulation:
• It is the intrinsic capacity of tissues to regulate their own blood flow.
• Found in many tissues like skeletal muscles, cardiac muscle, and brain
30. 2- Substances secreted by the endothelium:
A- Prostacyclin: -
• Cause vasodilatation & inhibits platelet aggregation
B- Nitric oxide (NO): -
• It is the endothelial derived relaxation factor (EDRF).
• It is an important vasodilator in many organs; however, it has
many other functions in other organs
31. HEART FAILURE
• It is failure of the heart to meet the metabolic demands of tissues.
• Causes include:
Severe anemia, severe hypertension, arrhythmia, myocardial infarction,
valvular disease and thyrotoxicosis.
• Heart failure can be classified as:
o Left sided HF (LHF): failure of the left side of the heart
o Right sided HF (RHF): failure of the right side of the heart
o Congestive HF (CHF): failure of the left & right sides of the heart
32. PHYSIOLOGICAL MECHANISMS IN HEART
FAILURE
• All the mechanisms in heart failure are stimulated by
hypotension and tissue hypoxia.
• These include activation of the renin-angiotensin-aldosteone
system because of the low blood supply to the kidney.
• This results in retention of sodium and water and therefore
contributes to edema formation.
33. • When the left ventricle fails to eject blood (LHF), blood
accumulates in the lung causing pulmonary edema
• When the right ventricle fails (RHF), blood accumulates in the
venous side causing raised JVP, hepatomegaly, ascites and lower
limb edema.
• When the two ventricles fail (CHF), blood accumulates in the lung
and the venous side; therefore, all symptoms and signs of LHF
and RHF are found in CHF
34. SHOCK
• When blood pressure falls so low that adequate blood flow to the
tissues can no longer be maintained, the condition known as shock
occurs
• Types
1. Hypovolemic shock (due to decreased blood volume)
2. Distributive or low resistance shock (due to vasodilatation)
3. Cardiogenic shock (due to cardiac lesion causing low COP)
4. Obstructive shock (due to obstruction of blood flow in the chest)
35. • Symptoms
• o Irritability (due to low blood supply to the brain)
• o Thirst (due to hypovolemia)
• o Palpitation (due to increased contractility of the heart for
compensation)
36. • Signs (Not in all types of shock)
o Pallor and cold clammy skin (due to vasoconstriction)
o Sweating (due to sympathetic activation)
o Tachycardia (due to sympathetic activation)
o Hypotension (due to hypovolemia, vasodilatation, cardiac lesion …)
o Low urine output (due to low renal blood flow and high release of
ADH)
o Hyperventilation (due to chemoreceptor stimulation by hypoxia or
acidosis)
37. Complications of shock
• Failure to treat shock leads to refractory or irreversible state.
Here a positive feedback mechanism is initiated (low COP= low
blood pressure= low venous return= low COP= low blood
pressure and so on) which leads eventually to death