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Human Body System Anatomy, Functions, Facts And Relation

The human body is complex, so it is not unexpected that there are numerous levels of structural organisation for the benefit of description, the human body can be thought about to be functionally arranged into different systems The levels of organization from easiest to many complex are chemical, cellular, tissue, organ, organ system, and organismal (the body as a whole).

Chemical Level

The chemical level includes atoms, molecules, and macromolecules. At the easiest level, the body is made up of chemical substances that are formed of atoms and molecules Atoms are the basic foundation of chemicals, and atoms integrate in particular methods to form molecules Some particles are remarkably little, such as water molecules, however, others might be large, such as the macromolecules of proteins Numerous small and big molecules are organized together to form organelles. An organelle is a microscopic subunit of a cell, rather like a small organ, that performs particular functions within a cell. Nuclei, mitochondria, and ribosomes are examples.

Cellular Level

Cells are the standard structural and practical systems of the body because all the processes of life happen within cells A cell is the most affordable level of organisation that lives. The human body is made up of trillions of cells, and several types of cells, such as muscle cells, blood cells, and nerve cells Each type of cell has a special structure that allows it to carry out particular functions.

Tissue Level

Comparable types of cells are typically organised together in the body to form a tissue Each body tissue includes an aggregation of similar cells that carry out comparable functions There are 4 important classes of tissues in the body: epithelial, connective, muscle, and nervous tissues.

Organ Level

Each organ of the body is made up of 2 or more tissues that interact, allowing the organ to perform its particular functions The body includes many organs, and each has a certain form and function. The stomach, heart, brain, as well as bones are examples of organs.

Organ System Level

The organs of the body are set up in practical groups so that their independent functions are collaborated to carry out particular system functions These collaborated, practical groups are called organ systems The digestive and nervous systems are examples of organ systems Many organs come from a single organ system. However, a couple of organs are appointed to more than one organ system For instance, the pancreas comes from both the digestive and endocrine systems.

SystemsSignificant Functions
Integumentary systemSecures versus environmental risks; assists manage body temperature
Skeletal systemSupplies assistance; secures tissues; shops minerals; types blood cells
Muscular systemProduces movement; supplies assistance; creates heat
Nervous systemDirects instant responses to stimuli, typically by collaborating the activities of other organ systems
Endocrine systemDirects long- term modifications in other organ systems
Cardiovascular systemTransportations cells and liquified products, consisting of gases, nutrients, and wastes
Lymphatic systemResists infection and disease; returns tissue fluid to the blood stream
Respiratory systemProvides air to sites where gas exchange takes place in between the air and flowing blood; produces sound
Digestive systemProcesses food and soaks up nutrients
Urinary systemRemoves excess water, salts, and wastes; controls pH
Reproductive systemProduces sex cells and hormones; supports embryonic development from fertilisation to birth (female)

Integumentary System

Secures versus environmental risks; assists manage body temperature

Skin is the outer covering of the human body. Its appendages consist of hairs, nails, sebaceous glands and sweat glands. The skin carries out following essential functions:

  • It functions as a physical barrier versus entry of microorganisms and other substances.
  • It avoids loss of water from the body.
  • It is an essential sensory organ consisting of receptors for touch and associated feelings.
  • It plays an essential role in managing body temperature.
Organ/StructureMain Function
Cutaneous Membrane
EpidermisCovers surface; secures much deeper tissues
DermisNurtures epidermis; supplies strength; includes glands
Hair RootsProduce hair; innervation supplies sensation
HairsOffer defence for head
Sebaceous glandsSecrete lipid finishing that oils hair shaft and epidermis
GlandProduce sweating for evaporative cooling
NailsSafeguard and stiffen distal pointers of digits
Sensory ReceptorsOffer feelings of touch, pressure, temperature, discomfort
HypodermisShops lipids; connects skin to much deeper structures

Skeletal System

The standard structure of the body is supplied by a a great deal of bones that jointly form the skeleton. At joints, the bones are unified to each other by fibrous bands called ligaments. In addition to the joints and bones, the skeletal system likewise consists of the cartilages present in the body.

Organ/StructureMain Function
Bones, Cartilages, and JointsAssistance, secure soft tissues; bones save minerals
Axial skeleton (skull, vertebrae, sacrum, coccyx, breast bone, supporting ligaments and cartilages)Secures brain, spinal cord, sense organs, and soft tissues of thoracic cavity; supports the body weight over lower limbs
Appendicular skeleton: limbs and supporting bones and ligamentsSupplies internal assistance and positioning of the limbs; assistances and moves axial skeleton
Bone MarrowMain site of blood cell production (red marrow); shops of energy in fat cells (yellow marrow)

Muscle System

Overlying and typically connected to the bones are different muscles Muscles are made up of numerous lengthened cells called muscle fibers which have the ability to agreement and unwind. 3 unique types of muscles can be determined which are skeletal muscles, smooth muscles and cardiac muscles.

Organ/StructureMain Functions
Skeletal MusclesOffer skeletal movement; control entryways to digestive and respiratory tracts and exits from digestive and urinary tracts; fruit and vegetables heat; assistance skeleton; secure soft tissues
Axial musclesAssistance and position axial skeleton
Appendicular musclesAssistance, move, and brace limbs
Tendons, AponeurosesUsage forces of contraction to carry out particular jobs

Nervous System

The specialised cells that make up the practical systems of the nervous system are called neurons The nervous system might be divided into:

  1. The central nervous system, comprised of brain and spinal cord
  2. The peripheral nervous system, including the peripheral nerves and the ganglia, connected with them.

The nerves providing the body wall and limbs are typically called cerebrospinal nerves. The nerves providing the viscera, in addition to the parts of the brain and spinal cord associated with them, make up the autonomic nervous system The autonomic nervous system is partitioned into 2 significant parts: the considerate and the parasympathetic nervous system.

Organ/StructureMain Function
Central Nervous System (CNS)Functions as nerve centre for nervous system; processes details; supplies short-term control over activities of other systems
BrainCarries out complex integrative functions; controls both activities
Spinal cordCommunicates details to and from brain; carries out less-complex integrative activities
Unique sensesOffer sensory input to the brain associating with sight, hearing, smell, taste, and stability
Peripheral Nervous System (PNS)Links CNS with other systems and with sense organs

Cardiovascular System

The cardiovascular system includes the heart and the blood vessels The blood vessels that take blood from the heart to different tissues are called arteries. The tiniest arteries are called arterioles. Arterioles open into a network of capillaries that perfuse the tissues Exchange of different substances in between the blood and the tissues take place through the walls of capillaries In some circumstances, capillaries are changed by a various little vessels called sinusoids. Blood from capillaries (or from sinusoids) is gathered by little venules which sign up with to form veins The veins return blood to the heart.

Organ/StructureMain Function
HeartMoves blood; keeps blood pressure
Blood VesselsDistribute blood around the body
ArteriesCarry blood from the heart to capillaries
CapillariesLicense diffusion in between blood and interstitial fluids
VeinsReturn blood from capillaries to the heart
BloodCarries oxygen, co2, and blood cells; provides nutrients and hormones; eliminates wastes; helps in temperature regulation and defence versus disease

Respiratory System

The respiratory system includes the lungs and the passages through which air reaches them. The passages are nasal cavities, the pharynx, the trachea, the bronchi and their intrapulmonary extensions.

Organ/StructureMain Function
Nasal Cavities and Paranasal SinusesFilter, warm, humidify air; identify smells
PharynxCarries out air to larynx; a chamber showed the digestive tract
LarynxSecures opening to trachea and includes vocal cords
TracheaFilters air; cartilages keep respiratory tract open
BronchiCarries out air in between trachea and lungs
LungsAccountable for air movement; alveoli within the lungs are sites of gas exchange in between air and blood

Digestive System

The digestive or the alimentary system consists of all those structures that are interested in consuming, and with digestion and absorption of food. The system includes an alimentary canal that includes the oral cavity, pharynx, oesophagus, stomach, little intestine and large intestine Other structures consisted of in the digestive system are the liver, the gall bladder and the pancreas.

Organ/StructureMain Function
Oral Cavity (Mouth)Cavity for food; deals with associated structures (teeth, tongue) to break up food and pass food and liquids to pharynx
Salivary GlandsOffer buffers and lubrication; produce enzymes that start digestion
PharynxCarries out strong food and liquids to esophagus; chamber is shown respiratory tract
EsophagusProvides food to stomach
StomachProduces acids, enzymes, and hormones
Small IntestineProduces digestive enzymes, buffers, and hormones; soaks up nutrients
LiverProduces bile; manages nutrition structure of blood
GallbladderShops and focuses bile for release into little intestine
PancreasProduces digestive enzymes and buffers; includes endocrine cells
Large IntestineEliminates water from faeces; shops wastes

Excretory System

Excretion is the elimination of waste products of metabolism from the body. Egestion (or defaecation) is the elimination of undigested food from the gut and is not considered excretion due to the fact that the product taken into the gut through the mouth is not made by the body itself. The organs forming excretory system are the kidney, the ureters, the urethra and the bladder.

Reproductive System

Reproduction is the production of a brand-new generation of people of the very same types. It includes the transmission of genetic product from one generation to the next. The male reproductive organs are the testis, the epididymis, the ductus deferens, the seminal vesicles, the prostate, the male urethra and the penis. The female reproductive organs are the ovaries, uterine tubes, the uterus, the vagina, the external genitalia and the mammary glands.


Organ/StructureMain Function
OvariesProduce oocytes and hormones
Uterine TubesProvide oocyte or embryo to uterus; regular site of fertilisation
UterusSite of embryonic development and exchange in between fetal and maternal blood streams; sheds lining throughout menstruation
VaginaSite of sperm deposition; functions as a birth canal throughout shipment; supplies passage for fluids throughout menstruation
External Genitalia
ClitorisIncludes erectile tissue; supplies satisfying feelings throughout sexes
LabiaContain glands that oil entryway to vagina
Mammary GlandsProduce milk that nurtures newborn baby


Organ/StructureMain Function
TestesProduce sperm and hormones
Accessory Organs

Epididymis Ductus deferens Seminal glands Prostate gland Urethra

Functions as site of sperm maturation in each testis Carries out sperm from the epididymis Secrete fluid that adds to semen Produces fluid and enzymes Carries out semen to outside
External Genitalia



Deposits sperm in vagina of female

Surrounds the controls and testes their temperature

Endocrine System

The endocrine tissue is comprised basically of cells that produce secretions which are put straight into blood called hormones. Some organs are completely endocrine in function. They are described as endocrine glands (or ductless glands) e.g. the hypophysis cerebri (pituitary gland), the pineal gland, the thyroid gland, the parathyroid glands and the suprarenal (adrenal) glands. Groups of endocrine cells might exist in the organs that have other functions These consist of the islets of Langerhans of the pancreas, the interstitial cells of the testis, the hair follicles and corpora lutea of the ovaries. Hormones are likewise produced by some cells in the placenta, the thymus and the kidney.

Organ/StructureMain Function
Pineal GlandMight manage timing of reproduction and set day-night rhythms
Pituitary GlandControls other endocrine glands; manages growth and fluid balance
Thyroid GlandControls tissue metabolic rate; manages calcium levels
Parathyroid GlandsManage calcium levels (with thyroid gland)
ThymusControls maturation of lymphocytes
Adrenal GlandsChange water balance, tissue metabolism, cardiovascular and respiratory activity
KidneysControl red blood cell production, raise blood pressure, and help in calcium homoeostasis
PancreasManages blood sugar levels
TestesAssistance male sexual characteristics and reproductive functions (Module 1.11)
OvariesAssistance female sexual characteristics and reproductive functions (Module 1.11)

Blood And Immune System

Blood is considered a customised connective tissue due to the fact that the cellular aspects of it are separated by a significant quantity of ‘intercellular substance’ and due to the fact that a few of the cells in it have close affinities to cells in basic connective tissue.

Flowing blood typically includes 3 primary types of cells which perform their particular physiologic functions:

  1. the red cells (erythrocytes) are mostly interested in oxygen transport
  2. the white cells (leucocytes) play different roles in the body defence versus infection and tissue injury and
  3. platelets (thrombocytes) which are mostly associated with preserving the stability of blood vessels and in avoiding blood loss.

Organismal Level

The greatest organisational level handling a person is the organismal level, the human organism as a whole. It is made up of all the interacting organ systems All the organisational levels from chemicals to organ systems add to the performance of the whole body.


  1. https://hal.archives-ouvertes.fr/docs/00/52/26/26/PDF/ap100005.pdf
  2. http://epjap.epj.org/articles/epjap/abs/2010/10/ap100005/ap100005.html
  3. http://hfs.sagepub.com/content/4/5/227.short
  4. http://users.dsic.upv.es/~mcarmen/docs/HumanBody.pdf
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