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NAME : SATHVIKA.A.P

ROLL NO:

2025-2026
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TOPIC-BLOOD PRESSURE
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This is to certify that this is the bonafide record of project work done by
master/miss of grade XII during the academic year 2025-2026.

Submitted for SSCE BIOLOGY practical examination held on / / at

Velammal Bodhi Senior Secondary, Ladanendal, Sivagangai district.

2025-2026

ACKNOWLEDGEMENT

First of all I wish to thank our beloved parents for providing us the
opportunity to study in VELAMMAL BODHI SENIOR SECONDARY SCHOOL,
Ladanendal.
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CONTENT

❖​ INTRODUCTION
❖​ BLOOD PRESSURE
❖​ TYPES OF BLOOD PRESSURE
❖​ DISORDER OF BLOOD PRESSURE
❖​ HOW IS DIABETES RELATED TO HIGH BLOOD PRESSURE
❖​ BLOOD PRESSURE IN ANIMALS
❖​ BLOOD PRESSURE DURING EXERCISE
❖​ MECHANISM OF MAINTAINING NORMAL BLOOD PRESSURE
❖​ METHOD OF MEASUREMENT OF BLOOD PRESSURE
❖​ HORMONAL REGULATIONS
❖​ CONCLUSION
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INTRODUCTION

Blood pressure is a silent disorder, which can affect anyone. Age, sex and
race play an important role. According to medical records, men are more likely
to be affected than women. Therefore, having a regular check of our blood
pressure after a certain age is important and could save your life from other
related complications.

The sphygmomanometer is an instrument used for measured in

millimetres of mercury(mmHg).

BLOOD PRESSURE

Blood pressure is the pressure of circulating blood against the walls of

blood vessels. Most of this pressure results from the heart pumping blood
through the circulatory system.

Sphygmomanometer has three parts: a cuff that can be inflated with

air, a pressure meter(manometer) for measuring air pressure in the cuff, and a
stethoscope for listening to the sound.

The blood makes as it flows through the brachial artery (the major
artery found in your upper arm).

TYPES OF BLOOD PRESSURE

❖​ SYSTEMIC ARTERIAL PRESSURE AND AGE

❖​ SYSTEMIC VENOUS PRESSURE

❖​ PULMONARY PRESSURE
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❖​ AORTIC PRESSURE

❖​ MEAN SYSTEMIC PRESSURE

SYSTEMIC ARTERIAL PRESSURE AND AGE

Fetal blood pressure

In pregnancy, it is the fetal heart and not the mother’s heart that builds
up the fetal blood pressure to drive blood through the fetal circulation . The
blood pressure in the fetal aorta is approximately 30 mmHg at 20 weeks of
gestation,and increases to approximately 45 mmHg at 40 weeks of gestation.

The average blood pressure for full-term infants:

Systolic 65-95 mmHg

Diastolic 30-60 mmHg

CHILDHOOD

In children the normal ranges for blood pressure are lower than for
adults and depend on height.Reference blood pressure values have been developed
for children in different countries, based on the distribution of blood pressure in
children of there countries.

STAGE APPROXIMATE SYSTOLIC BP, DIASTOLIC BP,

AGE mmHg mmHg

INFANTS 0-12 MONTHS 75-100 50-70

TODDLERS AND 1-5 YEARS 80-110 50-80

PRESCHOOLERS

SCHOOL AGE 6-12 YEARS 85-120 50-80

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ADOLESCENTS 13-18 YEARS 95-140 60-90

AGING ADULTS

In adults in most societies, systolic blood pressure tends to rise from early
adulthood onward, up to at least age 70; diastolic pressure tends to begin to rise
at the same time but start to fall earlier in mid-life, approximately age 55.
mean blood pressure rises from early adulthood, plateauing in mid-life, while
pulse pressure rises quite markedly after the age of 40. consequently, in many
older people, systolic blood pressure often exceeds the normal adult range, if the
diastolic pressure is in the normal range this is termed ISOLATED SYSTOLIC
HYPERTENSION. The rise in pluse pressure with age is attributed to increased
STIFFNESS OF THE ARTERIES. An age-related rise in blood pressure is not
observed in some isolated unacculturated communities.

SYSTEMIC VENOUS PRESSURE

Blood pressure generally refers to the arterial pressure in the SYSTEMIC

CIRCULATION. However, measurement of pressures in the venous system and
the PULMONARY VESSELS plays an important role in INTENSIVE CARE
MEDICINE but requires invasive measurement of pressure using a CATHETER.

Venous pressure is the vascular pressure in a VEIN or in the ATRIA

OF THE HEART. It is much lower than arterial pressure, with common values of
5 mmHg in the RIGHT ATRIUM and 8 mmHg in the left atrium.

VARIANTS OF VENOUS PRESSURE INCLUDE:

CENTRAL VENOUS PRESSURE, which is a good approximation of right

atrial pressure, which is a major determinant of right ventricular end diastolic
volume. (However, there can be exceptions in some cases.)

The JUGULAR VENOUS PRESSURE(JVP) is the indirectly observed

pressure over the venous system. It can be useful in the different forms of heart
and lung disease.
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The PORTAL VENOUS PRESSURE is the blood pressure in the PORTAL

VEIN. It is normally 5-10 mmHg

SITE NORMAL PRESSURE RANGE(IN

mmHg)

CENTRAL VENOUS PRESSURE 3-8

RIGHT VENTRICULAR SYSTOLIC 15-30

PRESSURE
DIASTOLIC 3-8

PULMONARY ARTERY SYSTOLIC 15-30

PRESSURE
DIASTOLIC 4-12

PULMONARY VEIN/ 2-15

PULMONARY CAPILLARY WEDGE

PRESSURE

LEFT VENTRICULAR SYSTOLIC 100-140

PRESSURE
DIASTOLIC 3-12

PULMONARY PRESSURE

Normally, the pressure in the PULMONARY ARTERY is about 15

mmHg at rest.

Increased blood pressure in the CAPILLARIES of the lung causes

PULMONARY HYPERTENSION, leading to interstitial EDEMA if the pressure
increases to above 20 mmHg, and to PULMONARY EDEMA at pressures above
25 mmHg.

AORTIC PRESSURE
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Aortic pressure, also called central aortic blood pressure, or central

blood pressure, is the blood pressure at the root of the aorta. Elevated aortic
pressure has been found to be a more accurate predictor of both cardiovascular
events and mortality, as well as structural changes in the heart, than has
peripheral blood pressure (such as measured through the brachial artery).
Traditionally it involved an invasive procedure to measure aortic pressure, but
now there are non-invasive methods of measuring it indirectly without a
significant margin of error.

Certain researchers have argued for physicians to begin using aortic

pressure, as opposed to peripheral blood pressure, as a guide for clinical
decisions. The way antihypertensive drugs impact peripheral blood pressure can
ofter be very different from the way they impact central aortic pressure.

MEAN SYSTEMIC PRESSURE

If the heart is stopped, blood pressure falls, but it does not fall to zero.
The remaining pressure measured after cessation of the heart beat and
redistribution of blood throughout the circulation is termed the mean circulatory
filling pressure; typically this is proximally 7 mmHg.

DISORDER OF BLOOD PRESSURE

HIGH BLOOD PRESSURE

Well first, blood pressure is the force of blood against your arteries and
the force at which your heart pumps your blood through your arteries.

High blood pressure, or Hypertension, is when your blood pressure is

abnormally high. Usually exceeding 140 over 90 mmHg(millimeters of mercury).

Some complications caused by high blood pressure are Stroke,

Atherosclerosis, heart attack, Congestive heart failure, and failure.
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RISK FACTORS OF HIGH BLOOD PRESSURE

CONTROLLABLE UNCONTROLLABLE

SMOKING AGE

ACTIVITY LEVEL ETHINICITY

DIET GENDER

DRUG USE FAMILY HISTORY

STRESS RACE

OVERWIGHT/OBESITY

ALCOHOL USE

HYPERTENSION

ATHEROSCLEROSIS
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HIGH CHOLESTEROL

HYPOTENSION

Hypotension, or low blood pressure, is when your blood pressure is much lower than
expected. It can happen either as a condition on its own or as a symptom of a wide
range of conditions. It may not cause symptoms. But when it does, you may need
medical attention.

HOW IS DIABETES RELATED TO HIGH BLOOD PRESSURE

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BLOOD PRESSURE IN ANIMALS

Blood pressure levels in non-human mammals may vary depending on the

species. Heart rate differs markedly, largely depending on the size of the animal (larger
animals have slower heart rates). The giraffe has a distinctly high arterial pressure of
about 190 mm Hg, enabling blood perfusion through the 2 metres (6 ft 7 in)-long neck to
the head. In other species subjected to orthostatic blood pressure, such
as arboreal snakes, blood pressure is higher than in non-arboreal snakes. A heart near
to the head (short heart-to-head distance) and a long tail with tight integument favor
blood perfusion to the head.

As in humans, blood pressure in animals differs by age, sex, time of day,

and environmental circumstances measurements made in laboratories or under
anesthesia may not be representative of values under free-living conditions. Rats, mice,
dogs and rabbits have been used extensively to study the regulation of blood pressure.

Blood pressure​
Heart rate​
mm Hg
Species beats per
minute
Systolic Diastolic

Blood pressure and heart

Calves 140 rate of various 75–146
mammals[114]

Cats 155 68 100–259

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Blood pressure​
Heart rate​
mm Hg
Species beats per
minute
Systolic Diastolic

Dogs 161 51 62–170

Goats 140 90 80–120

Guinea-pigs 140 90 240–300

Mice 120 75 580–680

Pigs 169 55 74–116

Rabbits 118 67 205–306

Rats 153 51 305–500

Rhesus monkeys 160 125 180–210

Sheep 140 80 63–210

Hypertension in cats and dogs

Hypertension in cats and dogs is generally diagnosed if the blood pressure is
greater than 150 mm Hg (systolic), although sight hounds have higher blood pressures
than most other dog breeds; a systolic pressure greater than 180 mmHg is considered
abnormal in these dogs.

BLOOD PRESSURE DURING EXERCISE

■​ BP changes with exercise.

■​ Conditions Blood pressure

■​ Before exercise 120/80 mmHg

■​ After mild exercise 140/80 mmHg

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■​ After heavy exercise 160/60 mmHg

■​ After mild exercise, systolic blood pressure increases while diastolic blood
pressure remains more or less the same.

■​ Following heavy exercise, the systolic pressure increases tremendously and the
diastolic pressure drops.

MECHANISM OF MAINTAINING NORMAL BLOOD

PRESSURE
There are several mechanisms through which the body regulates arterial
pressure.

Baroreceptor Reflex
In response to acute changes in blood pressure, the body responds through the
baroreceptors located within blood vessels. Baroreceptors are a form of mechanoreceptor that
become activated by the stretching of the vessel. This sensory information is conveyed to the
central nervous system and used to influence peripheral vascular resistance and cardiac
output.

There are two forms of baroreceptors.

1.​ High-Pressure Baroreceptors: Two baroreceptors are located within the high-pressure
arterial system:
1.​ The carotid baroreceptor responds to both increases and decreases in blood
pressure and sends afferent signals via the glossopharyngeal nerve (CN IX).
2.​ The aortic arch baroreceptor responds only to increases in blood pressure,
sending its signals through the vagus nerve (CN X).
2.​ Low-Pressure Baroreceptors

Antidiuretic Hormone

Antidiuretic hormone (ADH) is a hormone synthesized in the hypothalamus.

ADH is synthesized and released in response to multiple triggers which are:

1.​ High serum osmolarity, which acts on osmoreceptors in the hypothalamus

2.​ Low blood volume causes a decreased stretch in the low-pressure baroreceptors,
leading to the production of ADH
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3.​ Decreased blood pressure causes decreased stretch in the high-pressure

baroreceptors, also leading to the production of ADH
4.​ Angiotensin II.

ADH mainly functions to increase free water reabsorption in the collecting

duct of the nephrons within the kidney, causing an increase in plasma volume and
arterial pressure. ADH in high concentrations also causes moderate vasoconstriction,
increasing peripheral resistance, and arterial pressure.

Renin-Angiotensin-Aldosterone System (RAAS)

The renin-angiotensin-aldosterone system (RAAS) is a critical regulator of blood

volume and systemic vascular resistance.

While the baroreceptor reflex responds in a short-term manner to decreased

arterial pressure, the RAAS is responsible for more chronic alterations.
It does this by increasing sodium reabsorption, water reabsorption, and
vascular tone.

●​ It is composed of three major compounds: renin, angiotensin II, and aldosterone.

●​ These three act to elevate arterial pressure in response to decreased renal blood
pressure, decreased salt delivery to the distal convoluted tubule,
and/or beta-agonism.

Through these mechanisms, the body can elevate the blood pressure in a
prolonged manner.See image on the right.

Though the RAAS serves a critical function, it can be activated

inappropriately in several conditions that may then lead to the development of
hypertension. For example, renal artery stenosis results in a decreased volume of blood
reaching one (or both) kidneys resulting in the juxtaglomerular cells sensing a decrease
in blood volume, activating the RAAS. This can lead to an inappropriate elevation of
circulating blood volume and arteriolar tone due to poor renal perfusion.
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METHODS OF MEASUREMENTS
●​ PALPITORY

●​ AUSCULTATORY

PALPITORY METHOD
1) Localize the radial & brachial pulses.

​
2) Before you start, please ask the following
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questions:

a)​ Have you ever get your blood pressure checked?

If so, what is your blood pressure usually?

b)​ Are you in any medication for BP?

c)​ Did you do any exercise in the last half hour?

d)​ Did you have any tea, coffee or a cigarette in the

last half hour?

3)​ Support the arm horizontal at heart (mid-sternal) level

4)​ Inflate the BP cuff until a level which is about 20-30mmHg above the point at
which the pulse is no longer palpable

5)​ Now slowly deflate the cuff 2mm/sec until the pulse is palpable again.

▪ This is the systolic BP.

▪ In this method only the systolic pressure can be measured, while the diastolic
pressure cannot be measured.

AUSCULTATORY METHOD
The cuff pressure is inflated quickly to a pressure about 30 mm Hg higher
than the systolic pressure determined by the Palpitory method.

Then the air is let out of the cuff slowly.

At some point the person listening with the stethoscope will begin to hear
sounds with each heartbeat. This point marks the systolic pressure.

Continue to deflate until the point at which they disappear. This point marks
the diastolic pressure.

Repeat the procedure if you are unsure of the blood pressure.

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The sounds are called Korotkoff sounds.

METHOD OF MEASUREMENT OF BLOOD PRESSURE

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HORMONAL REGULATIONS
What are the hormones that regulate blood pressure?

Epinephrine and nor epinephrine, hormones secreted by the adrenal

medulla, raise blood pressure by increasing heart rate and the contractility of the
heart muscles and by causing vasoconstriction of arteries and veins.

What is the most powerful hormonal regulator of blood pressure?

Angiotensin II is a powerful vasoconstrictor, greatly increasing blood

pressure. It also stimulates the release of ADH and aldosterone, a hormone
produced by the adrenal cortex. Aldosterone increases the reabsorption of sodium
into the blood by the kidneys.
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CONCLUSION
These results highlight the importance of maintaining
healthy blood pressure for overall cardiovascular health. We
recommend adopting a balanced diet, engaging in regular
exercise, and managing stress to reduce the risk of
hypertension.
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REFERENCE

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