Cardiovascular/ Cieculatory System

Kardia ( latin word ) means Heart & Vasculum ( latin word ) means Vessele. So Cardiovascular system consists of Heart & Blood Vessele. So Cardiovascular system consists of Heart & Blood vessels. Cardiovascular system also known as Blood Circulatory System (as it circulates blood in the body).

Definition: The circulatory system is an organ system that moves nutrients, gases & wastes to & from cells, helps fight diseases & helps stabilize body temperature & pG to maintain homeostasis (equilibrium).

Organs of Cardiovascular system:
1, Heart
2, Blood vessels
3, Blood

Heart: It is a central pumping station which circulates blood to/from body by contraction & dilation. Heart receives blood by coronary blood vessel.

Blood Vessels: A tube carrying blood away from or toward the heart. Blood vessels are the means by which blood circulates throughout the body. Blood vessels are of two types – Artery & vein.

Artery: Carry blood (oxygenated blood) away from the heart except pulmonary artery. Pulmonary artery carries deoxygenated blood from heart to lung. Artery divides into small branches – arterioles, leading into many smaller vessels – capillaries.

Vein: Conveying blood (deoxygenated blood) toward the heart except pulmonary vein. Pulmonary vein carries oxygenated blood from lung to heart. Vein divides into small branches – venule, leading into many smaller vessels – capillaries.

Capillary: an extremely narrow blood vessel. Capillaries form networks in most tissues; they are supplied with blood by arterioles & drained by cenules. The vessel wall is only one cell thick, which enables exchange of oxygen, carbon dioxide, water, salts, etc. between the blood & the tissues.

In capillary blood supply O2 to the tissue & receive CO2 from the tissue. This blood is known as deoxygenated blood. This deoxygenated blood goes to the heart through vein & then to lung through pulmonary artery. In lung this blood (deoxygenated blood) expelled out CO2 & receive O2 (become oxygenated). This oxygenated blood goes to heart through pulmonary vein. Then this blood ( oxygenated blood) become circulates to the body through artery. In this way exchange of gases (oxygen & carbon dioxide) by the blood takes place in capillary.

Blood: Blood is a liquid connective tissue consists of blood plasma & blood cells.

Blood plasma (55%) consist of –

Water (90%), Mineral salt, Plasma protein, Food stuff, Gases in solution, Waste Products, Antibodies & antitoxins, Hormones from ductless glands, Enzymes, etc.

Blood cells (45%) consists of-
1, Red Blood Cell (RBC)
2, White Blood Cell (WBC)
3, Platelets

Red Blood Cell (RBC) – also known as erythrocyte containing the pigment “hemoglobin”, The principal function of which is the transport of oxygen ( as oxyhemoglobin). Oxyhemoglobin is a bright red substance formed after combines reversibly with oxygen. RBC is produced in red bone marrow of spongy bone.

White Blood Cell (WBC) – also known as leukocyte produced in red bone marrow of lymph node & spleen. It involved in protecting the body against foreign substances & in antibody production. Thus it plays an important role in body immune system.

Platelets – also known as thrombocyte plays an important role in blood coagulation.

Functions of blood:
1, It transport gases (O2 & C2), nutrients, hormones, enzymes, vitamins, etc.
2. Regulates body temperature, blood pressure, water & electrolytes balance.
3, Prevent hemorrhage (bleeding).

Blood Pressured:
It is the lateral pressure exerted by the blood to the vessel wall while flowing through it Blood

Pressure is of the following types:

1, Systolic blood pressure- maximum pressure during systole (contraction of heart)

Normal range: 100 – 140 mmHg

2, Diastolic blood pressure- minimum pressure during diastole (dilation of heart).
Normal range: 60 – 90 mmHg

Types of Circulatory system:
There are mainly three types of circulation occurs in human body & these are:

1, Systemic circulation- is the portion of the cardiovascular system which carries oxygenated blood away from the heart, to the body, & returns deoxygenated blood back to the heart.

2. Pulmonary circulation- is the portion of the cardiovascular system which carries oxygen- depleted blood away from the heart, to the lungs, & returns oxygenated blood back to the heart.

3, Coronary circulation- It provides a blood supply to the heart.


Blood flow in the body:

In capillary level blood receive CO2 from the tissue. This blood is called deoxygenated blood This deoxygenated blood drain to Heart (Right Atrium) through Capillary, Venule & vein. From Right Atrium blood goes to Right Ventricle of the Heart. Then this deoxygenated blood goes to Lung from Right Ventricle through pulmonary artery. In Lung this blood (deoxygenated blood) expelled out CO2 & receive O2 (become oxygenated) This oxygenated blood goes to Heart (Left Atrium) through pulmonary vein. From Left Atrium blood goes to Left Ventricle. Then this blood (oxygenated blood) become circulates to the tissues of the body from Left Ventricle of the Heart through Artery, Arteriole & Capillary. This oxygenated blood becomes deoxygenated after using by the tissues of the body. Again this deoxygenated blood goes to Lung for oxygenation & circulates in the body by the above way.

Common Diseases:

1, Hypercholesterolemia (hyperlipidaemia) – Raised cholesterol above normal limit in blood

1, Hypertension – Raised & sustained BP above normal limit is called hypertension.

3, Myocardial Infarction: Necrosis of heart muscle due to short supply of blood.

4, Ischemic Heart disease: Deficiency of blood supply in the heart.

5, Angina: Severe heart pain due to ischemia (inadequate blood flow to the heart).

 

Atherosclerosis:

Fatty deposits, celled plaque, may accumulate on the interior surface of the coronary arteries. This is particularly common in people who have high levels of cholesterol in their blood. Plaque deposits reduce the bore of the coronary arteries and thus the amount of blood they can carry.

So limit the blood supply to the heart that during times of stress the heart muscle is so deprived of oxygen that the pain of angina is created.

Trigger the formation of a clot causing a coronary thrombosis. this stops the flow of blood through the vessel and the capillary network it supplies causing a heart attack. The portion of the heart muscle deprived of oxygen dies quickly of oxygen starvation. If the area is not too large, the undamaged part of the heart can, in time, compensate for the damage.

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Classification of Nervous System

Nervous System is the most important system which control & integrates the different body functions & maintains the constancy of internal environment despite of extreme change in external environment.

Classification of Nervous System:

1, Central Nervous System – It consists of Brain (cranial part) & Spinal Cord.

2, Peripheral Nervous System – It consists of Cranial nerves (12pairs) & Spinal nerves (31 pairs).

Organs of Nervous System:

1, Brain -                      The enlarged & highly developed mass of nervous tissue contained within the cranium that forms the upper end of the CNS & is continuous below with the spinal cord. It is the controlling organ of the body. It regulates & coordinates body activities.

2, Spinal cord -            the portion of the CNS enclosed in the vertebral column, consisting of nerve cells & bundles of nerves connecting all parts of the body with the brain.

3, Nerves -                   a bundle of fibers that transmit impulses form the brain or spinal cord to the muscles & glands or inward from the sense organs to the brain & spinal cord.

                                    Cranial nerves – the 12 pairs of nerves that arise directly form the brain & leave the skull through separate apertures.

                                    Spinal nerves - the 31 pairs of nerves that leave the spinal cord & are distributed to the body, passing out from the vertebral canal through the spaces between the arches of the vertebrae.

4, Receptor -                present in the inner/outer side of nerve cell that receive impulses.Alfa, Beta, Histamine, Dopamine, etc.

5, Neurotransmitter - chemical substances present in synapse that carry impulses.

e.g. acetylcholine,   Dopamine, Serotonin, etc.

Neuron: Structural & functional unit of nervous system. A neuron consists of Dendrite, Cell body, Axon (nerve fiber), Myelin sheath, Axon terminal.

Process of transmission of impulse:

Dendrite of neuron receive impulse from axon of other neuron through neurotransmitter in the synapse. Then the impulse transmitted to cell body to axon & again to dendrite of other neuron. In this way impulse reaches to the brain. Reversely message from the brain reaches to periphery by this way.

Meninges -                   Thin layer covering brain & spinal cord.

Synapse -                     Synapse is the junction between two neurons where one neuron ends & other neuron begins.

Synaptic cleft -             minute gap in the junction of two neuron.

Common Diseases:

1, Anxiety

2, Depression

3, Hallucination

4, Mania, Phobia

5, Schizophrenia

6, Epilepsy.

7, Meningitis – Infection of meninges by Streptococcus pneumoniae.

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The Endocrine System

Endo means internal & crinos means secretion. So Endocrine means internal secretion.

Endocrinology is a branch of medical science which deals with the study of different endocrine glands of the body.

Endocrine gland: Means ductless gland which directly poured their secretion into the blood.

Endocrine system: The system which deals with endocrine glands & their secretions.

Organs of Endocrine System: The Endocrine System consists of the following glands.

1, Pineal gland

2, Hypothalamus

3, Pituitary gland – Anterior part & Posterior part.

4, Thyroid gland

5, Para – thyroid gland

6, Adrenal gland – Adrenal cortex & Adrenal medulla

7, Pancreas

8, Testis

9, Ovary

1, Pineal gland: A pea-sized mass of tissue attached by a stalk to the posterior wall of the third ventricle of the brain, deep between the cerebral hemispheres at the back of the skull. It may play a part in initiating the development of the gonads; in other mammals it secretes the hormone like substance melatonin. In humans, melatonin may be involved in the onset of puberty ( the time at which the onset of sexual maturity occurs).

2, Hypothalamus: The region of the forebrain in the floor of the third ventricle, linked with the thalamus above & the pituitary gland below. It contains several important centers controlling body temperature, thirst, hunger, eating, water balance & sexual function. It is also closely connected with emotional activity & sleep & functions as a center for the integration of hormonal & autonomic nervous activity through its control of pituitary secretions.

Major endocrine gland with their position, secreted hormone & function are follows:

 

Name of gland	position	Hormone	Function
Adrenal cortex	Outer portion of gland on top of kidney	cortisol, Aldosterone	Metabolism of carbohydrates, fat & Protein. Reduce sodium & increase K+ excretion by kidney.
Adrenal Medulla	Inner portion of gland surrounded by adrenal cortex.	Adrenaline, Nor-adrenaline	Increases carbohydrate use of energy.
Pancreas	In abdominal cavity	Insulin, Glucagons	Promotes glucose entry in cell & helps in carbohydrate metabolism. Increase the synthesis of & release of glucose from liver into body fluid.
Parathyroid	On back of thyroid gland	Parathormone	Controls calcium & phosphorus metabolism.
Pituitary, anterior	Front portion of small gland below hypothalamus	Growth hormone, TSH, FSH, Prolactin, Leutinizing hormone, Adrenocrticotropin	Influences growth, sexual development, skin pigmentation, thyroid function, adrenocortical function through effects on other endocrine gland.
Pituitary, Posterior	Back portion of small gland below hypothalamus	Antidiuretic hormone, Oxytocin	Antidiuretic hormone increases absorption of water by kidney tubule. Oxytocin increases urerine contraction.
Testes	In the scrotum	Testosterone	Stimulate the growth & development of male sexual characteristics.
Ovaries	In the pelvic cavity	Estrohen, Progesterone	Stimulate the growth & development of female sexual characteristics.
Thyroid	Two lobes in anterior portion of neck	Thyroxin, tri-iodothyronin, Calcitonin	Increases metabolic rate; indirectly influences growth & nutrition.

 TSH = Thyroid Stimulating Hormone, FSH = Follicle Stimulating Hormone

Hormone: Hormone is a chemical substance that is secreted into the internal body fluid by one cell or group of cell & excretes a physiological control effect on other cells of the body. 

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What is the Limbic System

Limbic System: It is a complex system of nerve pathways & networks in the brain, involving several different nuclei, that is involved in the expression of instinct & mood in activities of the endocrine & motor system of the body.

Function: Emotion, Intelligence, Mood Feeling, Memory, etc

Organs: Thalamus, Basal ganglia, Hippocampus & Amygdale.

Thalamus: One of two egg-shaped masses of gray matter that lies deep in the cerebral hemispheres in each side of the forebrain. The thalamus is relay stations for all the sensory messages that enter the brain, before they are transmitted to the cortex.

Basal ganglia: Several large masses of gray matter embedded deep within the white matter of the cerebrum. The basal ganglia have complex neural connections with both the cerebral cortex & thalamus. They are involved with the regulation of voluntary movements at a subconscious level.

Amygdale: A roughly almond-shaped mass of gray matter deep inside each cerebral hemisphere. It has extensive connections with the olfactory system & sends fibers to the hypothalamus; its functions are apparently concerned with mood, feeling, instinct & possibly memory for recent events.

Hippocampus: A swelling in the floor of the lateral ventricle of the brain. It contains complex folding of cortical tissues & is involved, with other connections of the hippocampus formation, in the workings of the limbic system.

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Lymphatic System

Organs: Lymphatic capillaries, Lymphatic vessels, Lymphatic nodes & Lymphatic ducts.

Function:     1, Collection of fluid & Protein from tissue spaces & back to
                         blood Stream.

                     2, Filtration of blood & formation of fresh lymphocytes.

                     3, Excretion, Defense, Circulation, etc.

Lymphatic System: A network of vessels that conveys electrolytes, water, proteins, etc, in the form of ‘lymph’ from the tissue fluids to the bloodstream. It consists of fine blind-ended lymphatic capillaries, which unite to form lymphatic vessels; at various points along the lymphatic vessels are `lymph nodes’. lymph drains into the capillaries & passes into the lymphatic vessels ,witch have valves to prevent backflow of lymph. The lymphatic leads to two large channels, the thoracic duct & the right lymphatic duct, which return the lymph to the bloodstream via the in nominate veins.

Lymph: The fluid present within the vessels of the Lymphatic System it consists of the fluid that bathes the tissues, which is derived from the blood & is drained by the lymphatic vessels. Lymph passes through a aeries of filters (lymph nodes) & is ultimately returned to the bloodstream via the thoracic duct. it is a similar in composition to plasma, but contains less protein & some cells, mainly lymphocytes (a variety of white blood cell).

Lymphatic capillaries: Arise in the spaces in the tissues as fine hair-like vessels with porous walls. These gather up excess fluid from the tissues & unite to form the lymphatic vessels.

Lymphatic vessels: The lymphatic vessels are thin-walle, collapsible tubes similar in structure to the veins, but carrying lymph instead of blood.

Lymphatic nodes: A number of small swellings found at intervals along the lymphatic system. They are composed of lymphoid tissue & acts as filters for the lymph, preventing foreign particles from entering the blood stream; they also produce lymphocytes.

Lymphatic ducts: After filtration by the nodes the lymph is emptied by the lymphatic vessels into the two lymphatic ducts, the thoracic duct & right lymphatic duct.

Common Diseases of lymphatic System:

1, Lymphadenitis- Inflammation of lymph nodes (swollen, painful & tender nodes).

2, Lymphangitis- Inflammation of lymphatic vessels.

3, Lymphoma- Malignant tumor of lymph nodes.

  LYMPHATIC SYSTEM

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