Blood pressure is one of the important vital signs. This ppt is for the First year General Nursing and Midwifery (GNM) students to understand the topic with simple language and pictures
Blood pressure is one of the important vital signs. This ppt is for the First year General Nursing and Midwifery (GNM) students to understand the topic with simple language and pictures
HEART RATE
REGULATION OF HEART RATE
VASOMOTOR CENTER – CARDIAC CENTER
MOTOR (EFFERENT) NERVE FIBERS TO HEART
FACTORS AFFECTING VASOMOTOR CENTER
for all medical & health care students
Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...Physiology Dept
Definition of cardiac output and related terms
Measurement of cardiac output
Variations in cardiac output
Regulation of cardiac output
Cardiac output control mechanisms
Role of heart rate in control of cardiac output
Integrated control of cardiac output
Heart–lung preparation
SEMINAR ON BLOOD PRESSURE REGULATION, Determinants of Arterial BP
Functions Of Blood Pressure
Physiological Variations In Bp
Blood Pressure Regulation
Applied Physiology
Arterial pulse (The Guyton and Hall Physiology)Maryam Fida
It is the pressure wave which travel along the walls of Arteries when blood is ejected from the left ventricle into the aorta
Aorta expands to accommodate the ejected blood volume, when it expands it has got elastic recoil, so it shortens back. This causes pressure wave which leads to expansion of arterial wall which can be palpated as arterial pulse.
Normally arterial pulse ends at arterioles.
So normally there is no capillary pulsations
FACTORS
The velocity of blood flow
The velocity of transmission of pressure wave
A closed system of the heart and blood vessels
The heart pumps blood
Blood vessels allow blood to circulate to all parts of the body
The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products
A closed system of the heart and blood vessels
The heart pumps blood
Blood vessels allow blood to circulate to all parts of the body
The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products
Cardiovascular system (blood pressure, hypertension) Pharmacy Universe
The circulatory system, also called the cardiovascular system or the vascular system, is an organ system that permits blood to circulate and transport nutrients (such as amino acids and electrolytes), oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases, stabilize temperature and pH, and maintain homeostasis.
The circulatory system includes the lymphatic system, which circulates lymph.[1] The passage of lymph for example takes much longer than that of blood.[2] Blood is a fluid consisting of plasma, red blood cells, white blood cells, and platelets that is circulated by the heart through the vertebrate vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues. Lymph is essentially recycled excess blood plasma after it has been filtered from the interstitial fluid (between cells) and returned to the lymphatic system. The cardiovascular (from Latin words meaning "heart" and "vessel") system comprises the blood, heart, and blood vessels.[3] The lymph, lymph nodes, and lymph vessels form the lymphatic system, which returns filtered blood plasma from the interstitial fluid (between cells) as lymph.
Regulation of arterial blood pressure (The Guyton and Hall Physiology)Maryam Fida
BLOOD PRESSURE
The pressure exerted by the blood on vessel wall is known as blood pressure.
SYSTOLIC BLOOD PRESSURE
The maximum pressure exerted in the arteries during systole of heart.
Normal systolic pressure: 120 mm Hg.
DIASTOLIC BLOOD PRESSURE
The minimum pressure exerted in the arteries during diastole of heart.
Normal diastolic pressure: 80 mm Hg.
PULSE PRESSURE
The difference between the systolic pressure and diastolic pressure.
Normal pulse pressure: 40 mm Hg (120 – 80 = 40).
MEAN ARTERIAL BLOOD PRESSURE
The average pressure existing in the arteries.
Mean Arterial Blood Pressure = Diastolic Pressure + 1/3 Pulse Pressure
Pulse Pressure = (Systolic – Diastolic)
Mean Arterial Blood Pressure =Diastolic Pressure+1/3(Systolic – Diastolic)
This presentation gives you a brief, understandable, captivating and presentable idea on the physiology of blood pressure regulation both on hypertension and hypotension cases.
HEART RATE
REGULATION OF HEART RATE
VASOMOTOR CENTER – CARDIAC CENTER
MOTOR (EFFERENT) NERVE FIBERS TO HEART
FACTORS AFFECTING VASOMOTOR CENTER
for all medical & health care students
Cardiac output by Dr. Amruta Nitin Kumbhar Assistant Professor, Dept. of Phys...Physiology Dept
Definition of cardiac output and related terms
Measurement of cardiac output
Variations in cardiac output
Regulation of cardiac output
Cardiac output control mechanisms
Role of heart rate in control of cardiac output
Integrated control of cardiac output
Heart–lung preparation
SEMINAR ON BLOOD PRESSURE REGULATION, Determinants of Arterial BP
Functions Of Blood Pressure
Physiological Variations In Bp
Blood Pressure Regulation
Applied Physiology
Arterial pulse (The Guyton and Hall Physiology)Maryam Fida
It is the pressure wave which travel along the walls of Arteries when blood is ejected from the left ventricle into the aorta
Aorta expands to accommodate the ejected blood volume, when it expands it has got elastic recoil, so it shortens back. This causes pressure wave which leads to expansion of arterial wall which can be palpated as arterial pulse.
Normally arterial pulse ends at arterioles.
So normally there is no capillary pulsations
FACTORS
The velocity of blood flow
The velocity of transmission of pressure wave
A closed system of the heart and blood vessels
The heart pumps blood
Blood vessels allow blood to circulate to all parts of the body
The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products
A closed system of the heart and blood vessels
The heart pumps blood
Blood vessels allow blood to circulate to all parts of the body
The function of the cardiovascular system is to deliver oxygen and nutrients and to remove carbon dioxide and other waste products
Cardiovascular system (blood pressure, hypertension) Pharmacy Universe
The circulatory system, also called the cardiovascular system or the vascular system, is an organ system that permits blood to circulate and transport nutrients (such as amino acids and electrolytes), oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases, stabilize temperature and pH, and maintain homeostasis.
The circulatory system includes the lymphatic system, which circulates lymph.[1] The passage of lymph for example takes much longer than that of blood.[2] Blood is a fluid consisting of plasma, red blood cells, white blood cells, and platelets that is circulated by the heart through the vertebrate vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues. Lymph is essentially recycled excess blood plasma after it has been filtered from the interstitial fluid (between cells) and returned to the lymphatic system. The cardiovascular (from Latin words meaning "heart" and "vessel") system comprises the blood, heart, and blood vessels.[3] The lymph, lymph nodes, and lymph vessels form the lymphatic system, which returns filtered blood plasma from the interstitial fluid (between cells) as lymph.
Regulation of arterial blood pressure (The Guyton and Hall Physiology)Maryam Fida
BLOOD PRESSURE
The pressure exerted by the blood on vessel wall is known as blood pressure.
SYSTOLIC BLOOD PRESSURE
The maximum pressure exerted in the arteries during systole of heart.
Normal systolic pressure: 120 mm Hg.
DIASTOLIC BLOOD PRESSURE
The minimum pressure exerted in the arteries during diastole of heart.
Normal diastolic pressure: 80 mm Hg.
PULSE PRESSURE
The difference between the systolic pressure and diastolic pressure.
Normal pulse pressure: 40 mm Hg (120 – 80 = 40).
MEAN ARTERIAL BLOOD PRESSURE
The average pressure existing in the arteries.
Mean Arterial Blood Pressure = Diastolic Pressure + 1/3 Pulse Pressure
Pulse Pressure = (Systolic – Diastolic)
Mean Arterial Blood Pressure =Diastolic Pressure+1/3(Systolic – Diastolic)
This presentation gives you a brief, understandable, captivating and presentable idea on the physiology of blood pressure regulation both on hypertension and hypotension cases.
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
20.2 Blood Flow, Blood Pressure, and Resistance Get This Book!.docxfelicidaddinwoodie
20.2 Blood Flow, Blood Pressure, and Resistance
Get This Book!
Page by: OpenStax
Summary
By the end of this section, you will be able to:
· Distinguish between systolic pressure, diastolic pressure, pulse pressure, and mean arterial pressure
· Describe the clinical measurement of pulse and blood pressure
· Identify and discuss five variables affecting arterial blood flow and blood pressure
· Discuss several factors affecting blood flow in the venous system
Blood flow refers to the movement of blood through a vessel, tissue, or organ, and is usually expressed in terms of volume of blood per unit of time. It is initiated by the contraction of the ventricles of the heart. Ventricular contraction ejects blood into the major arteries, resulting in flow from regions of higher pressure to regions of lower pressure, as blood encounters smaller arteries and arterioles, then capillaries, then the venules and veins of the venous system. This section discusses a number of critical variables that contribute to blood flow throughout the body. It also discusses the factors that impede or slow blood flow, a phenomenon known as resistance.
As noted earlier, hydrostatic pressure is the force exerted by a fluid due to gravitational pull, usually against the wall of the container in which it is located. One form of hydrostatic pressure is blood pressure, the force exerted by blood upon the walls of the blood vessels or the chambers of the heart. Blood pressure may be measured in capillaries and veins, as well as the vessels of the pulmonary circulation; however, the term blood pressure without any specific descriptors typically refers to systemic arterial blood pressure—that is, the pressure of blood flowing in the arteries of the systemic circulation. In clinical practice, this pressure is measured in mm Hg and is usually obtained using the brachial artery of the arm.
Components of Arterial Blood Pressure
Arterial blood pressure in the larger vessels consists of several distinct components (Figure): systolic and diastolic pressures, pulse pressure, and mean arterial pressure.
Systolic and Diastolic Pressures
When systemic arterial blood pressure is measured, it is recorded as a ratio of two numbers (e.g., 120/80 is a normal adult blood pressure), expressed as systolic pressure over diastolic pressure. The systolic pressure is the higher value (typically around 120 mm Hg) and reflects the arterial pressure resulting from the ejection of blood during ventricular contraction, or systole. The diastolic pressure is the lower value (usually about 80 mm Hg) and represents the arterial pressure of blood during ventricular relaxation, or diastole.
Systemic Blood Pressure
The graph shows the components of blood pressure throughout the blood vessels, including systolic, diastolic, mean arterial, and pulse pressures.
Pulse Pressure
As shown in Figure, the difference between the systolic pressure and the diastolic pressure is the pulse pressure. For example, an indivi ...
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 .
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
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.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
(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. BLOOD PRESSURE
Arterial blood pressure can be defined as the lateral pressure
exerted by the moving column of blood on the walls of the arteries.
measured as mmHg.
Changes in pressure are the driving force that moves blood through
the circulatory system.
3. 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 the lymph.
4. NORMAL VALUES
Normal Adult range
Can fluctuate within a
wide range and still
be normal
Systolic/diastolic
100/60 - 140/80
5. Normal Adult range
Can fluctuate within a
wide range and still
be normal
Systolic/diastolic
100/60 - 140/80
The maximum pressure during
ventricular contraction is called
the systolic pressure. Normal
range (90-140 mm Hg).
The lowest pressure that
remains in the arteries before
the next ventricular contraction
is called the diastolic pressure.
Normal range (60 -90 mm
Hg).
Arterial blood pressure rises and falls according to cardiac cycle
phases.
6. Pulse pressure is a measure of
the strength of the pressure
wave.
Denotes the difference between
systolic and diastolic pressure.
7. Mean arterial pressure is estimated as diastolic pressure
plus one-third of pulse pressure.
Mean arterial pressure is closer to diastolic pressure
than to systolic pressure because diastole lasts twice as
long as systole.
8. Mean arterial pressure (MAP) is a function of cardiac output
and resistance in the arterioles (peripheral resistance).
The cardiac output is defined as the volume discharged from the
ventricle per minute.
Peripheral resistance defined as the resistance to flow offered by
the arterioles
BP = Cardiac output X PR
9. FACTORS MAINTAINING BLOOD PRESSURE
Cardiac output (CO= SV X PR)
Circulating blood volume
(This mainly affects systolic B.P)
Elasticity of the vessel wall
Peripheral resistance.
10. RECORDING OF
BLOOD PRESSURE
Palpatory method
Auscultatory method
PALPATORY METHOD which records the pressure at
which the subject feels the first pulse in the artery.
The detected pressure is systolic pressure.
12. AUSCULTATORY METHOD in which the researcher detects the pulse by
listening via a stethoscope placed in the antecubital fossa over the brachial
artery.
When the cuff pressure is higher than the systolic pressure, no sound is to be
heard.
The pressure at which the first sound is heard is the systolic pressure, at which
the blood flow resumes and is turbulent.
As the cuff pressure continues to drop, the sound becomes muffler and finally
disappears.
The pressure at which the sound disappears was the considered the diastolic
pressure
14. HYPERTENSION:
High blood pressure, clinically
diagnosed when above 140/90
mmHg.
HYPOTENSION:
Low blood pressure, clinically
diagnosed when below 100/60
mmHg.
15. REGULATION OF
BLOOD PRESSURE
SHORT TERM
BARO RECEPTOR
REFLEX
HORMONES
CHEMORECEPTOR
REFLEX
LONG TERM
RENIN
ANGIOTENSIN
ALDOSTERONE
SYSTEM
16. NEURAL REGULATION
REGULATION OF BLOOD PRESSURE
Achieved through the role of cardiovascular centers
located in the medulla oblongata and baroreceptor
stimulation
This cluster of neurons responds to changes in
blood pressure as well as blood concentrations of
oxygen, carbon dioxide, and other factors such as
pH.
Baroreceptor: A nerve ending that is sensitive to
changes in blood pressure.
17. CARDIO ACCELATORY CENTRE
• SYMPATHETIC
CARDIO INHIBITORY CENTRE
• PARASYMPATHETIC
CARDIAC CENTER
Autonomic control of heart
18. VASOMOTOR CENTER
Autonomic control of blood vessels
Stimulation of vasomotor
center:VASOCONSTICTION
Inhibition of vasomotor
center: VASODILATION
19. BARORECEPTOR FUNCTION Receptors located within thin areas
of blood vessels and heart chambers
that respond to the degree of stretch
caused by the presence of blood.
Send impulses to the cardiovascular
center to regulate blood pressure.
Vascular baroreceptors are found
primarily in sinuses (small cavities)
within the aorta and carotid arteries.
The aortic sinuses are found in the
walls of the ascending aorta just
superior to the aortic valve, whereas
the carotid sinuses are located in the
base of the internal carotid arteries.
23. CHEMICAL VASOCONSTRICTION
Increased concentration of calcium (Ca2+ ions) and phosphorylated
myosin within vascular smooth muscle cells.
A signal transduction cascade leads to increased intracellular calcium
from the sarcoplasmic reticulum through IP3 mediated calcium
release.
Enhances calcium entry across the sarcolemma through calcium
channels.
The rise in intracellular calcium interacts with calmodulin, which in
turn activates myosin light chain kinase.
24. This enzyme is responsible for phosphorylating the light chain of myosin to
stimulate cross-bridge cycling.
Once elevated, the intracellular calcium concentration is returned to its basal
level through a variety of protein pumps and calcium exchanges located on
the plasma membrane and sarcoplasmic reticulum.
This reduction in calcium removes the stimulus necessary for contraction
allowing for a return to baseline.
Endogenous vasoconstrictors include ATP, epinephrine, and angiotensin II.
25. Vasodilation is modulated by calcium ion concentration and myosin
phosphorylation within vascular smooth muscle cells.
Dephosphorylation by myosin light-chain phosphatase and induction of calcium
symporters and antiporters that pump calcium ions out of the intracellular
compartment both contribute to smooth muscle cell relaxation and therefore
vasodilation.
This is accomplished through reuptake of ions into the sarcoplasmic reticulum via
exchangers and expulsion across the plasma membrane.
Endogenous vasodilators include arginine and lactic acid.
CHEMICAL VASODILATION
28. ANTIDIURETIC HORMONE: VASOPRESSIN
Increased release by
posterior pituitary gland in
response to decreased
blood pressure and
decreased blood volume.
Promotes water
reabsorption by kidneys
Vasoconstriction of vessels
29. RENAL REGULATION
When blood volume is low, renin, excreted by the kidneys, stimulates
production of angiotensin I, which is converted into angiotensin II. This
substance has many effects, including increase in blood pressure due to
its vasoconstrictive properties.
The cells that excrete renin are called juxtaglomerular cells. When blood
volume is low, juxtaglomerular cells in the kidneys secrete renin directly
into circulation. Plasma renin then carries out the conversion of
angiotensinogen released by the liver to angiotensin I.
Aldosterone secretion from the adrenal cortex is induced by angiotensin
II and causes the tubules of the kidneys to increase the reabsorption of
sodium and water into the blood, thereby increasing blood volume and
blood pressure.
31. REFERENCES:
Rodney Rhoades, David R. Bell Medical
Physiology: Principles for Clinical Medicine.
http://www.interactive-biology.com/4301/blood-
pressure-short-term-and-long-term-control-
measures/
Boundless Anatomy and Physiology
