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Anatomy and Physiology of the Human Body
BiologyHuman biology

Introduction

Anatomy of the human body describes the structure and relationship between all organs. On the other hand, the physiology of the human body describes the functions of all organs. All the organ systems of the body work together to perform a particular task or a group of tasks. Anatomy and physiology are closely related and constitute various organ systems like the respiratory system, digestive system, nervous system, cardiovascular system, urinary system, and reproductive systems. The functions of these systems help in body growth and development as well as make the body healthy and fertile.

What do you understand by Human Anatomy?

The branch deals with the structure of the human body are called Human Anatomy. The term “anatomy” comes from the Greek words “ana” (up) and “tome” (cutting)”. So, anatomy means cutting up or dissecting the body. Anatomy is the organisation of the body system arranged with cells, tissues, organs and organ systems. It is categorised into different groups and they are as follows-

  • Gross anatomy - Involves the inspection of organs on a larger scale by dissection.

  • Cellular anatomy - Involves investigating of cells and cellular components by microscope.

  • Molecular anatomy - Involves the study of biochemical levels like DNA, RNA, proteins etc.

Structure of Human body and parts

Cells are a structural and functional unit of life. Cells, tissue, organ, organ system and organism sequentially form a higher level of organisation.

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Human Physiology

The branch deals with all the events, activities and functions of vital processes of the living system. The word Physiology originates from the Greek word “physiología”. Different types of physiology include-

  • Cell physiology - Deals with the functions of cells and cellular components.

  • Special physiology - Deals with functions of specific organs.

  • Systemic physiology - Deals with the function of the body systems.

  • Pathophysiology - Deals with the effects of diseases on organ or system functions.

Circulatory system

Circulation or transport of body fluid like blood or lymph throughout the body cells to provide nutrients and to collect nitrogenous waste with the help of the heart, arteries, veins, and blood is called the Circulatory system. This is also known as the cardiovascular system. Closed circulatory systems are found in the human body.

Organ Structure and Components Functions

Heart

The human heart has a specialised cardiac muscle with many valves and four chambers- right and left atrium and right and left ventricle.

Pumps blood through the network of arteries and veins.

Arteries

(blood vessels)

Thick-walled, valve less.

Transport blood from the heart to other parts of the body (exception- pulmonary artery).

Veins

(blood vessel)

Thin-walled and having valves.

Transport blood from the other parts of the body to the heart (Exception- pulmonary vein).

Capillaries

Thinnest blood vessels.

Connects arteries and veins.

Blood

50–55 % of blood is plasma and 45-50% blood cells like RBC, WBC and platelets.

Act as the medium of transport.

Respiratory System

Respiration is the process in which oxidation of food materials takes place to liberate energy by the two phases of respiration- external and internal respiration. In external respiration, oxygen is inhaled by inspiration and Carbon dioxide is exhaled with the help of the diaphragm, intercostal muscles etc. In internal respiration or cellular respiration, food is broken down to liberate ATP. The main respiratory organ is a pair of Lungs which contain the alveoli. In the following table, respiratory organs are arranged sequentially.

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Digestive system

Digestion is the process by which the breakdown of food materials takes place with the help of several enzymes secreted from the digestive tract, liver, pancreas, and gallbladder. Digestion includes five steps-

Steps Involved organs Function

Ingestion

In the buccal cavity (teeth, tongue, and palate).

Intake of food materials.

Digestion

Mouth, salivary glands, liver, stomach, pancreas, small intestine.

Convert insoluble food particles into soluble and absorbable forms.

Absorption

Villi is found in the internal surface of the small intestine.

Transport digested products into the blood or lymph.

Assimilation

Cells, tissues.

Incorporation of absorbed products into tissue.

Egestion

Large intestine and anus.

Excretion of unusable or undigested material from a cell.

The food path through the digestive tract or gastrointestinal tract consists of the following organs-

Reproductive System

Reproduction is the process in which an organism can produce offspring similar to itself. Human only follows sexual reproduction and shows dimorphism. There are different reproductive organs in the male and female sexes. The reproductive system consists of two groups of organs. They are-

  • Primary sex organs- They produce gametes like ovum and sperm.

  • Secondary sex organs- They transport and sustain the gametes and give nourishment to the developing baby.

Female Reproductive System

Female reproductive system produces eggs (ova), ensures fertilisation, saves and nurses a fertilised egg to develop into a foetus, gives birth, lactates etc. This system is located in the pelvic region of the female body. Female sex organs and their function are as follows-

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Sex organs Functions

Ovaries (two in no.)

Oogenesis and ovulation

Genital Tract (Fallopian Tubes, Uterus, Vagina)

Fertilisation, ovulation, carrying a baby and giving birth.

External Genitalia

Respond to sexual stimulation.

Mammary Gland

Produce milk.

Male Reproductive System

Male reproductive system can produce sperm, participate in sexual intercourse, transport sperm and discharge sperm into the female reproductive tract. This system is located in the pelvic region of the male body. Male sex organs and their function are as follows-

Sex organs Functions

Testis (two in no.)

Secreting testosterone and producing sperm.

Epididymis

Develop the sperm.

Ejaculatory ducts

Transport mature sperm to the urethra

Urethra

Ejaculating semen.

Nervous system

The nervous system is the important controlling, regulatory, and communicating system in the body. This system transmits signals to the brain and whole body with the help of neurons, nerves, and ganglia and directs the ability to move, breathe, see, think, learn, memory and more. Neurons consist of axons, Dendron, cell body etc.

The main two parts of the nervous system are

  • Central nervous system- It consists of the brain and spinal cord.

  • Peripheral nervous system- It consists of the Somatic nervous system and the Autonomic nervous system.

Urinary system

Urinary or renal systems can produce, store and secrete the waste fluid urine with the help of a nephron. This system consists of the following parts-

Organ Function

Kidney (one pair)

Remove waste products and balance the body's fluids.

Ureter (one pair)

Bring urine downward.

Bladder (one)

Store urine temporarily.

Urethra (one)

Pass the urine outside the body.

Immune system

The immune system can encounter various pathogens and produce antibodies to protect the body from diseases. Major organs and cells of the Immune System are as follows-

  • Organs- Spleen, Thymus, Lymph Nodes, Blood, etc.

  • Cells- Stem cells, T-lymphocytes, B-lymphocytes, Monocytes, B-Cells, T-cells (Cytotoxic and Helper), Neutrophils etc.

Conclusion

Every cell, tissue, organ and organ system works specifically to make the body alive. After the function of the digestive system absorbed nutrients circulated and reached every cell through the function of the circulatory system. Assimilated food particles are broken down to release energy by the function of the respiratory system. This energy is used in body activity, growth, development, reproduction etc. The nervous system and endocrine system coordinate the total body system to fulfil all requirements. In this way, all the body systems depend on each other to complete the set of tasks.

FAQs

What is Villi?

In the inner lining of the small intestine, millions of tiny finger-like structures are projected to absorb the digested food nutrients called villi.

What is immunoglobulin?

Immunoglobulin is the protein which is made by B cells and plasma cells to protect the body from infection. They are classified into five categories like IgG, IgM, IgA, IgD, and IgE.

What are the major parts of the nephron?

The major parts of the nephron are the glomerulus, Bowman's capsule, and the renal tubule.

Where haemoglobin is specifically found in humans?

Iron-rich protein haemoglobin is found in the red blood cells. It binds with oxygen and carbon dioxide to transport.

What do you mean by closed circulatory system?

In this system of circulation, the heart pumps blood through the blood vessels to keep blood separate from body tissues. Annelids, Birds, and Mammals show this type of circulatory system.

References

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