Blood Pressure Measurement

 Blood Pressure Measurement

Blood pressure is the force exerted by blood against the walls of arteries and veins. It is created by the pumping action of the heart. Blood pressure is measured in millimeters of mercury (mm Hg) and is expressed by two numbers—120/80, for example. The higher number is systolic blood pressure, the maximum pressure that occurs when the heart contracts. The lower number is diastolic blood pressure, the pressure when the heart is relaxed between contractions.

 Equipment

1. Sphygmomanometer (A sphygmomanometer consists of an inflatable bag inside a covering called a cuff, an inflating bulb, a manometer from which blood pressure can be read, and a valve that is used for deflation.)

2. Stethoscope

3. Chair

4. Table or another surface to support arm

Sphygmomanometer

Preparation

For the person being tested: Wear clothing that allows your upper arm to be bare. Avoid heavy exercise or eating prior to the test. Don’t smoke or ingest caffeine for at least 30–60 minutes before being tested. Sit quietly for several minutes before the test begins.

 

Instructions

1. The subject should sit comfortably, with the arm slightly flexed, palm up, and the forearm supported at  heart level on a table or other smooth surface. If such a surface isn’t available, you will need to support the subject’s forearm while you take the measurements.

2. Place the deflated cuff on the subject’s upper arm, with the lower edge of the cuff about 1 inch above the inner elbow crease. The inflatable bag should rest on the brachial artery, which is on the inner part of the upper arm. The inflatable bag should encircle at least 80% of the arm; if it does not, use a larger sphygmomanometer.

3. Apply the stethoscope lightly to the arm, just at the inner elbow crease. Make sure the stethoscope doesn’t touch the cuff or any of the tubing from the sphygmomanometer.

4. While watching the manometer and listening for pulse sounds through the stethoscope, inflate the bag about 30 mm Hg above the point at which pulse sounds disappear. (Inflating the bag closes off the blood flow in the brachial artery, causing the pulse sounds to stop.)

5. Slowly deflate the bag at a rate of about 3 mm Hg per second (or per heartbeat). As you release the pressure, pulse sounds will become audible, go through several changes in clarity and intensity, and then disappear again. You must listen carefully to the pulse sounds while you watch the readings on the manometer.

• Systolic pressure is the point at which pulse sounds first become audible. You should hear faint but clear tapping sounds.

• Diastolic pressure is the point at which the pulse sounds disappear.

 

Blood Pressure Classification Average the results of the two sets of measurements. Refer to the table below for the rating.

 

Average pressure: _______ / _______ Classification: ____________________

 

(systolic)                        (diastolic)

 Categorya                     Systolic (mm Hg)                                        Diastolic (mm Hg)

Normalb                        Below 120                     and             Below 80

Prehypertension             120–139                        or                80–89

Hypertensionc Stage 1 140–159 or 90–99 Stage 2 160 and above or 100 and above

 

Result: Blood pressure of  own/ person is ------ (mmHg) Systolic -------  (mmHg) Diastolic  mmHg.

 

Histology study

Histological structure of Pancreas

1.     The section showed the following characters:

2.     Two distinct regions are observed: the exocrine pancreas and the endocrine

3.     The exocrine pancreas is composed of numerous acinus.

4.     The acinus is composed of small pyramidal cells, the acinar cells; whose nucleus is situated at the base of the cell.

5.     The acinar cells shows all the characteristic features of a protein secreting cells: presence of golgi bodies, ribosomes, RER,etc.

6.     The endocrine pancreas is a pale staining region also called as the islet of langerhans.

7.     Routine stains shows the presence of two types of cells

A.   the acidophil cells or the α cells and

B.   The basophilic cells or the β cells.

 8.     Using immunocytochemical techniques four types of cells are identified – the A, B, D and F cells.

9.     α cells have regular granules with a dense core surrounded by a clear region bounded by a membrane.

10.                        β cells have irregular granules with a core formed of irregular crystals of insulin.

11.                        Presence of a complex network of capillaries with fenestrated endothelium. 

THYROID GLAND

Introduction

1.     It’s the only endocrine gland that is situated superficially in the body, for this reason reachable for physical examination.

2.     It’s the only endocrine gland that depends on external environment for raw material, iodine, to synthesize its hormones.

3.     It’s the only endocrine gland, which doesn’t pour its hormones into blood immediately after formation but stores them and after that discharges them in blood to be used as and when needed.

4.     It’s one of the organs of the body having an extremely rich blood circulation.

 

Location

The thyroid gland lies in the lower part of the front and side of the neck reverse to Structure

Presence of numerous spherical follicles, the thyroid follicles.

• In each follicle, lie cuboidal or columnar follicular cells on the basement membrane.

• The follicles have a central dark staining nucleus.

• The basal part of the follicular cell is rich in RER.

• The apical pole has a discrete golgi complex and small secretory granules.

The thyroid gland contains 2 types of secretory cells:

1.     follicular

2.     parafollicular.

 

The follicular cells are cuboidal epithelial cells creating the wall of spherical thyroid follicles. They secrete 2 hormones: thyroxine and triiodothyronine.

Thyroglobulin is the storage form of thyroxine and is an iodinated glycoprotein.

• Another kind of cells, called the parafollicular cell is present either as a part of

Functions of thyroxin

1.     These hormones are necessary for normal growth and development, especially of the skeletal and nervous system.

 

 

Thyroid is a bilobed gland. The two lobes lie on either sides of larynx.The two lobes are connected by isthamus. They secrete a hormone called "Thyroxine". It is rich "iodinated hormone". It contains an aminoacid called "Thyroxine". Thyroxine increases the metabolic activities. Hence it maintains B.M.R [Basal metabolic Rate]. The thyroxine is essential for metamorphosis in frog. It is also essential for tissue differentiation

If the thyroid glands are removed in tadpole larva of frog it fails to undergo metamorphosis. When such thyroid free tadpole larva is fed with thyroid glands, it undergoes metamorphosis. If normal young tad poles are fed with thyroxine, they metamorphose into frogs prematurely [the normal period of metamorphosis is reduced].

 In human beings, failure of thyroid secretion in child hood leads to mental retardation. This disease is called "cretinism". Defeciency of thyroid secretion in adults produces "Myxedema". Hyper thyroidsm leads to "exophthalmic goiter" or Grave's disease. Less secretion in the aged persons leads to the swelling of lobes of thyroid. The disease is called simple goitre.

 

 

  T. S. of Pituitary Gland of a Mammal

 

T. S. of anterior lobe of  pituitary gland of a mammal shows the following

histological structures:

1.The pituitary gland is more or less rounded in  shape and occurs at the base of brain just beneath the diencephalon.

2. It composed of three lobes namely , anterior   lobe, intermediate lobe and posterior lobe.

3.The anterior lobe  forms the largest part of the   pituitary gland formed of three distinct kinds of cells differing in their staining reaction :

1.  basophil cells , 
2.  acidophil cells 
3. chromophobes.

4. Usually on the outside are the basophil cells which are stained by basic stains.

5.In the centre are found acidophil or Oxyphil cells   Which take acidic stains.

6.The chromophobe cells are indifferent to either  basic or acid stains. They are found scattered    throughout the anterior lobe.

7.Antrior lobe produces many hormones , namely   somatotrophic hormone , thyrotrophic   hormone, adrenocorticotropic hormone,   gonadotrophic hormone  and , thus , controls   growth , development of sex glands as well as the   activities of thyroid,   parathyroid and adrenal glands.

8.Intermediate lobe is composed of cell cords with  colloid filled  follicles. It produces an  intremedin  hormone.

9.postrior lobe is composed of neuroglial  cells  connective tissue fibres and blood vessels.    It produces Pituitrin, vasopressin, and oxytocin  Hormones.

10.The pituitary gland is an endocrine gland of  utmost importance to organisms. It is called  master gland.            

ADRENAL GLANDS

There are two adrenal or supra renal glands situated longitudinally on the ventral surface of kidneys. These are orange-colored glands. The outer part of each gland is called "cortex" and the inner part is called "medulla". 

The cortex of adrenal gland is stimulated by A.C.T.H. of the pituitary. But medulla is not stimulated by the pituitary gland. The cortex secretes gluco corticoids, mineral corticoids and sex corticoids.

Glucocorticoids:  These increase blood glucose level by the synthesis of glucose from proteins. It is called "gluconeogenesis". Blood glucose level is also increased by the convertion of glycogen to glucose. It is called "glycogenolysis".

Mineral corticoids:  These maintain water and salt balance.

 Sex corticoids: These stimulate the development of secondary sexual characters.

Excessive secretion of sex corticoids in women causes the development of male secondary sexual characters like "beard" and "moustaches". The disease is called "virilism". Defeciency of mineral corticoids leads to bronze pigmentation in skin. The disease is called "Addison's disease".

The central part or medulla of the adrenal gland secretes two amines, "epinephrine" [adrenaline] and "norepinephrine" [noradrenaline]. These regulate the blood pressure, heart beat, respiration, contractions and relaxations of smooth muscles. The epinephrine prepares the individual for meeting stress or emergency. Hence the adrenal medulla is considered as the gland for "fight, fright and flight". 

 

Body defense or Immune system

 

Immunology has its origins in the study of how the body protects itself against infectious diseases caused by microorganisms, such as bacteria, viruses, protozoa, and fungi, and also parasitic organisms, such as helminth worms.

 

The immune system is made up of special organs, cells and chemicals that fight infection (microbes). 

 Two major mechanisms that protect the body:

1. Innate, nonspecific system of

2. Adaptive system that fights specific pathogens

 

1.     Innate, Nonspecific Resistance

Physical Barriers

1st major level of protection from invasion and infection

nonspecific –To prevent entry of athogens into body

1. Intact Skin

tightly packed cells filled with waxy keratin thick, multiple layers of dead keratinized cells shed regularly rarely, if ever, penetrated while intact only a few parasitic worms (cercariae) can do this.

If skin is broken:

·        staphs and streps are most likely to get in sebaceous glands provides protective film over skin.

·        acidity of skin secretions ('acid mantle') inhibit bacterial & fungal growth; also contains bacteriocidal chemicals but

·        if skin is moist, not cleaned frequently enough may permit yeasts and fungi already present to become a problem.

2. Mucous Membranes

·        line all systems that open to outside of body nasal hairs trap pathogens mucous thick, sticky, traps pathogens.

Cilia; in respiratory system move mucous out of system coughing and sneezing speed up process

3. Gastric juices; secreted by lining of stomach contains HCl and enzymes; highly acidic (pH~1.3-3.5) kill and dissolve most bacteria and toxins except S. aureus and C. botulinum

 

4. Lacrimal Apparatus:

continual blinking flushes and wipes away pathogens lysozyme kills and dissolves some bacteria. (lysozyme also found in sweat, saliva, and nasal secretions)

5. Saliva:

continual flushing of bacteria to stomach lysozyme kills and dissolves some bacteria.

6. Urine:

continual flushing of bacteria entering urethra low flow  bladder infection acidity also inhibits bacterial growth

7. Vaginal Secretions:

flushing and trapping pathogens in mucous acidity inhibits bacterial growth but: some pathogens thrive in moisture and if they occur in large enough numbers they are able to penetrate eg. Treponema

 

 

Parts of the immune system

The main parts of the immune system are:

 

a)     White blood cells

b)    Complement system

c)     Lymphatic system

d)    Spleen

e)     Bone marrow

f)      Thymus.

g)     Tonsil

h)    Antibodies

 

White blood cells

White blood cells are the key players in your immune system. They are made in your bone marrow and are part of the lymphatic system.

White blood cells move through blood and tissue throughout your body, looking for foreign invaders (microbes) such as bacteria, viruses, parasites and fungi. When they find them, they launch an immune attack.

White blood cells include lymphocytes (such as B-cells, T-cells and natural killer cells), and many other types of immune cells.

 

Lymphatic system

The lymphatic system is a network of delicate tubes throughout the body. The main roles of the lymphatic system are to manage the fluid levels in the body

react to bacteria deal with cancer cells deal with cell products that otherwise would result in disease or disorders

absorb some of the fats in our diet from the intestine.

The lymphatic system is made up of:

 

Lymph nodes (also called lymph glands) -- which trap microbes

lymph vessels -- tubes that carry lymph, the colourless fluid that bathes your body's tissues and contains infection-fighting white blood cells.

 

Spleen

The spleen is a blood-filtering organ that removes microbes and destroys old or damaged red blood cells. It also makes disease-fighting components of the immune system (including antibodies and lymphocytes).

 Bone marrow

Bone marrow is the spongy tissue found inside your bones. It produces the red blood cells our bodies need to carry oxygen, the white blood cells we use to fight infection, and the platelets we need to help our blood clot.

 

Thymus

The thymus filters and monitors your blood content. It produces the white blood cells called T-lymphocytes.

 

Bone marrow:

 is the primary lymphoid organ .It is a soft tissue within the cavity of bones .Bone marrow .

Majority of lymphid progenitors develop into B- lyphocytes in the bone marrow. Some of lymphoid progenitors migrate into the thymus , where they develop into the T-lypmhocytes. During secondary immune response large number of plasma cells are produced in the bone marrow.

 

They secrete large amount of abs. So bone marrow is a source of ab synthesis. The bone marrow is the site of generation of all circulating blood cells in the adult including lympocytes and is the site of B- cell maturation

•         The white blood cells of the immune system are known as Lymphocytes.  These WBC   are also found in the spleen and blood.

•         Lymphocytes are wbcs that activate the immune response. 

 

 

Tonsil:

•         clusters of lymphatic cells and extracellular matrix not completely surrounded by a connective tissue capsule.

•         Consist of multiple germinal centers and crypts

•         Several groups of tonsils form a protective ring around the pharynx.

–       pharyngeal tonsils (or adenoids) in nasopharynx

–       palatine tonsils in oral cavity

–       lingual tonsils along posterior one-third of the tongue

 

Antibodies

Antibodies help the body to fight microbes or the toxins (poisons) they produce. They do this by recognising substances called antigens on the surface of the microbe, or in the chemicals they produce, which mark the microbe or toxin as being foreign. The antibodies then mark these antigens for destruction. There are many cells, proteins and chemicals involved in this attack.

.

ANTIBODY STRUCTURE

 

 An antibody (Ab), also known as an immunoglobulin (Ig)

 It’s a large Y-shape protein produced by B cells that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses.

The antibody recognizes a unique part of the foreign target, called an antigen.

 Antibody composed of four polypeptide chains – two identical heavy chains and two identical light chains.

 

1.     two heavy chain

2.     two light chain

3.     constant region

4.     variable region

5.     hinge region

6.     Fab fragment(antigen-binding fragment)

7.     Fc fragment(crystallizable fragment ) and

8.     disulfide bond present

Composed of 4 polypeptide chains.

 • 2 identical light and 2 identical heavy chains

 • Linked by disulphide bonds

 • Light chains similar in all immunoglobulins

• Light chains occur in 2 varieties kappa and lambda

• Light and Heavy chains are subdivided into variable and constant region.

 • Each heavy and light chain contains amino terminal in variable region, carboxyl terminal in constant region

• Each immunoglobulin peptide chain has intra chain disulphide bonds- form loops

 • Antibody or immunoglobulin basically glycoprotein, made by activated B cell called a plasma cell. antibody protects ageist foreign material (antigen)and  foreign bacteria.

 

Each heavy chain and light chain connected by disulfide bonds. Two identical light chain consists of about 220 amino acid and mass of approximately 25,000 Da and each heavy chain consists of about 440 amino acid and 50,000 to 70,000 Da mass.

 Both light (L) and heavy (H) chains contain two different regions.

 · Constant (C) regions

· Variable (V) regions

 

The constant region in both chains has an amino acid sequence that does not vary significantly between antibodies of the same class. When variable regions both chain vary significantly from antibodies and they contain different amino acids of different antibodies.

 

Both variable regions folded together, and from the antigen-binding site. That region antigen bite with antibodies.

 

An antibody can tag a microbe or an infected cell for attack by other parts of the immune system, or can neutralize its target directly. • The production of antibodies is the main function of the humoral immune system.

• Antibodies are secreted by a type of white blood cell called a plasma cell.

 

 

Classification • Based on structure and antigenic nature of H chain the immunoglobulins are classified into 5 classes.

1.     Ig G- (gamma)

2.     Ig A- (alpha)

3.     Ig M- (mu)

4.     Ig D- (delta)

5.     Ig E - (epsilon)

Immunity:

 

• The response is directed at specific targets and is not restricted to initial site of infection

• delay in  time occurs between exposure and maximal response

• The adaptive immune system allows for a stronger immune response as well as immunological memory, where each pathogen is "remembered" by its signature antigen

• Antigens are proteins or carbohydrate chain of a glycoprotein within a plasma membrane

• The specific immune response is antigen-specific and requires the recognition of specific “non-self” antigens during a process called antigen presentation

• Antigen specificity allows for the generation of responses that are tailored to specific pathogens or pathogen-infected cells.

• The ability to mount these tailored responses is maintained in the body by "memory cells“

• Should a pathogen infect the body more than once, these specific memory cells are used to quickly eliminate.

 

There are two types of immunity:

 

2.     Humoral Immunity: or Antibody Mediated Immunity (AMI; )defends against extracellular pathogens by binding to antigens and making them easier targets for phagocytes and complement proteins •

3.     Celluralr immunity  – defends against intracellular pathogens and cancer.

 

 

1.     Humoral or antibody-mediated response –

It is also termed  anti-body mediated because B cells produce antibodies. because antibodies are released into the blood stream.

 B cells - are produced and mature in the bone marrow – they possess a protein on the outer surface known as the B-cell receptor (BCR) which allows them to bind to a specific  antigen

Plasma B cells also known as plasma cells,  produce antibodies 

Memory B cells – ready for the next invasion

4.     B cell comes into contact with antigen on microbe.

5.     it attaches to the antigen and becomes an antigen-presenting B-cell with antigen-MHC complex.

• Helper T cell that binds to the complex

• Helper T secretes interleukin that stimulates mitosis in B cells so they multiply

• Some B cells mature into plasma cells and other become memory cells

• The plasma cells produce antibodies also called immunoglobins – proteins which attach to the antigens.

• Antibodies can clump microbes for destruction, mark microbes for destruction by phagocytes, activate complement proteins that rupture/lyse microbe cell membranes or infected host cells.

 

 

 

Cellular Immunity: Cell Mediated Immunity = CMI or T cell Immunity

Mediated by T lymphocytes (T-cells)

involves a more diverse group of cells than for B cell activation usually, slower to respond antigens are usually larger than in AMI .

 

T-Cell Development & Activation

 

1. Probably also first develop in fetal liver from stem cells

2. Then move to thymus where they develop and proliferate

3. Move into lymph nodes and spleen as t- cells

4. T-cells cannot recognize free antigens in the blood generally need cell to cell contact to work

A. Specific T cells activated by exposure to a specific antigen eg. Viral infected cell, cancer cell, bacterial cell

B. Initiate clonal selection and multiplication

C. Differentiation into several cell types

D. Various t-cells secrete immunoactive chemicals =lymphokines;=cytokines, not antibodies which direct the activities of both b and t cells and phagocytes

 

T cells mature into helper t cells which regulate immunity by increasing the response of other immune cells

• memory T cells persist sometimes for life and protect in case of re-infection

 

Significance of immune system

·         The immune system is a complex network of cells and proteins that defends the body against infection. 

·         The immune system keeps a record of every germ (microbe) it has ever defeated so it can recognise and destroy the microbe quickly if it enters the body again.

·         Abnormalities of the immune system can lead to allergic diseases, immunodeficiencies and autoimmune disorders.