1.3 System physiology – structure and function of various systems in brief
Role
Principal Investigator
Name
Dr. AsisGoswami
CoPrincipalInvestigator
Paper Coordinator
Dr. P.K. Nag
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Dr. AsisGoswami
Content Reviewer
Dr. AmitavaChatterjee
Language Editor
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Items
Subject Name
Paper Name
Module Name/Title Case
Study
Module Id
Pre-Requisites
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Dr. AsisGoswami
Affiliation
Ramakrishna Mission Vivekananda
University
Ramakrishna Mission Vivekananda
University
Ramakrishna Mission Vivekananda
University
Ramakrishna Mission Vivekananda
University
Ramakrishna Mission Vivekananda
University
Description of Module
Physical Education, Sports and Health
Education
Exercise Physiology
System Physiology
PESHE/RKMVU/5/1.3
Module 1.1 -Introduction
Given in learning outcome
System Physiology, Cell, Tissue, organ
Learning Objectives
1. Reading this module the student will get brief idea about the structure- function
relationship of a cell.
2. He will also learn about the constituents of human body from cell to system
and their functions.
1. Introduction
The human body is an extremely complex structure made up of large number of
elements. Different aspects of the human body can be studied by understanding different
levels of organizational that make a functional mechanism. A number of elements
combine to produce compounds, known as biological compounds or biochemical or
organic compounds. Carbon remains the base of organic matter although it is present in
the body as the second highest quantity. Common elements found in living tissues, in
sequence of the quantity present, are Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen
(N), calcium (Ca) and Phosphorus (P). It is very difficult to estimate the quantity of each
element in the human body. Many studies on cadaver (body of dead human) have
indicated chemical composition of human being. Table below gives nearest value of
presence of these elements in the body (Wang et al, 1992) (Table 1).
Table 1: Elemental level of body composition
Name of the element
Oxygen
Carbon
Hydrogen
Nitrogen
Calcium
Phosphorus
Potassium, Sulfur, Sodium,
Chlorine and Magnesium
Trace elements Copper, Chromium,
Iron, Cobalt, iodine, etc.
Percentage in
the body
61.0-65.0
18.0-23.0
10.0
2.6-3.0
1.4
1.0
<1.0 each total
of these is about
1.2 %
Less than 1.0%
in total
Carbon, hydrogen, oxygen & nitrogen (and sometimes phosphorus & sulfur) combine in
various ways to form biomolecules like Carbohydrates (sugars and starch), Proteins,
Lipids (fats), and Nucleic acid (DNA & RNA). Note that about 60- 70% of human body is
water and 40-30% is solid material (see the figure below, Fig. 1).
Figure 1: Gross composition of human body
2. Structural unit of the body- The Cell
Robert Hooke in the year 1665 found that cork was formed of small cells. Later on
Schwann (1839)reported that all the living body consists of small compartments and
these were named as “Cell”. With the development of modern microscopes minute detail
of cells became available. Human body is a collection of individual cells.Cells are the
basic structural and functional units of the human body. All types of cells contain
common structures, called as intracellular structures (Organelle). However, there are
exceptions such as matured red blood cell does not have a nucleus. A diagram of a
common cell and brief description of its structural components are given below (Fig. 2).
Cell Membrane:Structure and shape of the cell is defined by the outer covering of the
cell known as Cell membrane.Cell membrane is the protective boundary of the cell. It
separates the cell from the environment. The membrane has selective permeability and
allows movement of molecules in and out of the cell by passive and active transport
mechanisms.
Cytoplasm: All the sub structures of a cell are floating in a fluid called as Cytoplasm.It is
the jelly like liquid substance present inside the cell membrane. Different organelles of
the cell are present in the cytoplasm. So many biochemical reactions including protein
synthesis and ATP formation occurs in cytoplasmic organelles.
Mitochondria: It is called as the ‘Power house of the Cell’. Many energy producing
chemical reactions and cellular respiration take place in this organelle. This is the site of
aerobic metabolism.
Nucleus: It is the largest organelle in a cell. It contains different components such as
the nuclear envelope, chromosomes, and the nucleolus. Nucleus holds the genetic
material DNA and makes mRNA. Nucleus contain a sub-organelle called nucleolus.
Nucleolus primarily serves as the site of ribosome synthesis and assembly.
Golgi Apparatus: Also known as the Golgi complex, Golgi body, or simply the Golgi, It
was identified in 1897 by the Italian physician Camillo Golgi and named after him in
1898.It is the organelle responsible for modification and sorting of proteins. It packages
proteins into membrane-bound vesicles inside the cell and these vesicles are sent to
their destination.
Rough Endoplasmic Reticulum: They are network of membranes or sac like
structures named as cisternae. These cisternae are held together by cytoskeleton. The
rough surface is due to adherence of ribosomes. Rough endoplasmic reticulum stores
and transport material throughout the cell.
Smooth Endoplasmic Reticulum: Similar structure like rough endoplasmic reticulum.
They synthesize of lipids, metabolism of carbohydrates and helps in detoxification from
drugs and poisons. It also store calcium ions (specially in skeletal muscle cells).
Ribosome: These are small granule like structures either present attached to the
endoplasmic reticulum or as free structures. They take up mRNA and produce protein
through a process called translation.
Figure 2: Image of a model cell.
(Picture of the cell modified from the archive of a small project by Andy Schmitz to
archive Creative Commons-licensed copies of all the books which were available online
from a specific publisher at the end of 2012.
http://2012books.lardbucket.org/books/introduction-to-chemistry-general-organic-andbiological/index.html)
Vacuole: They are membrane bound storage space containing water, salt, and other
important substances. Vacuoles take part in breaking down of food particles and actually
function as digestive system in a cell.
Lysosome: Lysosomes are also membrane bound storage space capable of breaking
more complex food materials. They act as waste disposal system of the cell by digesting
the unwanted material.
Centrioles: Centrioles are cylinder like structures made of protein, located
withincentrosome and remain as a pair. These are centre of cell division
3. The Tissue – Second level of Structural Unit
Human body cells are generally arranged in an organized way in small groups
performing a set of specific function. Such a collection or a group of similar types of cells
having same function is known as Tissue. Four types of tissues found in human body;
they are:
3.1
Epithelial
Epithelial tissues are specialized cells that protect different organs of the body.
They cover surface of the body (skin) and also internal organs like digestive tract,
reproductive tract, and air passage. These tissues also perform secretive function and
absorption. Epithelial tissue is classified by their shape, number of layers and
appearance. In this picture I have shown the cells classified by their shape.
Classification by Cell Shape
There are four categories of epithelia based on cell shape:
1. Squamous – Cells look flat or sometimes shield-like (Fig.3).
Figure 3: Squamous epithelial cells under microscope.
(Source:http://en.wikipedia.org/wiki/Epithelium#/media/File:Cheekcells_stained.jpg)
2. Cuboidal – These cells look like boxes and hold nearly same height and width.
They appear box-like. The nucleus is spherical and found in the center of the cell
(Fig. 4).
Figure 4: Cuboidal Cells
(Source:http://commons.wikimedia.org/wiki/File:Gray1133.png)
3. Columnar – The cells looks tall and the width is relatively less. The nucleus is
placed in the bottom of the cell. Presence of microvilli and ciliaare characteristic
feature in these cells.(Fig. 5).
Figure 5: Image of Columnar Cells
(Source:http://commons.wikimedia.org/wiki/File:Normal_gastric_mucosa_intermed_mag.jpg)
4. Transitional epithelium – The appearance of transitional epithelial cells depending
on the organ where it is present. In case of small stretching the cells appear like
balloon or full cell. Distension of the organ makes the epithelium flattened. (Fig.6).
Figure 6: Transitional epithelium in prostate gland
(Source:http://commons.wikimedia.org/wiki/File:Corpora_amylacea_intermed_mag.jpg)
3.2 Muscular
Muscle is the tissue that gives movement to the body parts. These cells are classified
based on different characteristics:
Microscopic feature: Striated ( cardiac and skeletal muscle) and non-striated (smooth
muscle)
Site of presence: Cardiac (heart), Skeletal (attached with bone) and visceral (in viscera –
intestine, blood vessel, respiratory tract, etc.)
Skeletal muscles are the largest group of muscle in terms of mass, about 40 % of the
body mass.
Muscle (also called as myocytes) is elongated cells ranging from several millimeters to
about 10 centimeters in length and from 10 to 100 micrometers in width. These cells are
joined together in tissues that may be either striated or smooth. Striation is observed due
to the arrangement of myofibrillar contractile proteins called myofilaments. Striated
muscle is further classified as either skeletal or cardiac muscle. Skeletal muscle is also
called as voluntary muscle since it is under conscious control, while smooth muscle and
cardiac muscles are not (Fig. 7).
Skeletal muscle
Cardiac muscle
Smooth muscle
Figure 7: Different types of muscle tissue.
(Source:http://commons.wikimedia.org/wiki/File:414_Skeletal_Smooth_Cardiac.jpg
http://teaching.ncl.ac.uk/bms/wiki/index.php/File:Lrg-1348-skeletal_muscle.jpg)
Skeletal muscle is anchored to the bone by tendons (or by aponeuroses at a few places)
and is used to create skeletal movement such as locomotion and to maintain posture.
Though postural control is generally maintained as an unconscious reflex the muscles
responsible also react to conscious control like non-postural muscles. An average adult
male is made up of 42% of skeletal muscle and an average adult female is made up of
36% (as a percentage of body mass).
Cardiac muscle (known as myocardium), are found only in the heart, and is a striated
muscle similar in structure to skeletal muscle but not subject to voluntary control. They
contain sarcomeres and are packed into highly regular arrangements of bundles.
Cardiac muscle branches out in irregular angles. The resulting fibers are again branched
and interconnected in complex networks. This helps in spreading the electrical impulse.
Each cell has a single nucleus. Cardiac muscle is controlled involuntarily by SA node for
pumping blood through the heart chambers into the blood vessels.
Smooth muscle, neither striated in structure nor under voluntary control, is found within
the walls of organs and structures such as
theesophagus, stomach, intestines,bronchi, uterus, urethra, bladder, blood vessels, and
the skin. They are also called as visceral muscles. They taper at both ends and do not
show striation. Cell junctions hold them together and they are bundled together in a
connective tissue sheath.
3.3 Connective
These are fibrous or hard tissues composed of cells separated by extracellular material
(matrix). Examples are bone and blood (Fig.8).
Stained blood smear
Image of Hard portion of bone
(Source: http://commons.wikimedia.org/wiki/File:Blood_smear.jpg
http://commons.wikimedia.org/wiki/File:Gray73.png)
Figure 8: Examples of connective tissue.
Connective tissue is found in between other tissues everywhere in the body, including
the central nervous system. The outer membranes covering the brain and spinal cord are
the meningescomposed of connective tissue.
All connective tissue apart from blood and lymph consists of three main components:
fibers, (elastic and collagenous fibers),ground substance and cells. Blood and lymph lack
the fiber component. All are immersed in the body water.
Connective tissue can be broadly subdivided into connective tissue proper, special
connective tissue, and series of other, less classifiable types of connective
tissues.Connective tissue proper consists of loose connective tissue and dense
connective tissue. Special connective tissue consists of reticular connective
tissue, adipose tissue, cartilage, bone, and blood. Other kinds of connective tissues
include fibrous, elastic, and lymphoid connective tissues. In the picture stained blood
smear can be seen.
3.4 Nervous
Nervous tissue is comprised of cells of the nervous system (both peripheral and central).
These tissues carry electrical impulses and perform many complex functions. Cells of the
nervous tissue are known as neurons (Fig.9).
Histological section of nervous tissue
A nerve cell
Figure 9: Examples of nervous tissue
(Source:http://commons.wikimedia.org/wiki/File:Grey_matter_and_white_matter_-_intermed_mag.jpg
http://en.wikipedia.org/wiki/Neuron#/media/File:Neuron_Hand-tuned.svg)
4. Human Body organs
Collection of different tissues (at least two tissue types) performing set of specific
functions is called as organ. The heart, liver, stomach, intestines, lungs, pancreas, and
brain are examples of organs (Fig.10).
Image of Liver
Image Heart
Figure 10: Example of organs (adapted from Gray & Carter, 1858)
5.
Body system
A system is a collection of two or more organs performing a group of activities. Systems
of the human body are inter-linked and affect functioning of each other. Any kind of
stimulus or disturbance in one system is spread to other systems also.
Sr. Name of the
no system
Components of the system
Functions performed by the
system
1
Bone, cartilage, ligaments
and tendons. There are 206
bones in the body. The
skeleton is generally divided
in three sets: axial skeleton,
appendicular skeleton and
auditory ossicles.
Axial part consist of vertebral
column (26) , skull (22), hyoid
bone (1) and ribs with
sternum (25) (total number
74).
Appendicular skeleton consist
of Upper (64) and Lower
extremities (62). Total
number bone is 126.
The auditory system contains
six small bones.
It consists of striated skeletal
muscle (visceral muscle not
included). Human body has
about 650 skeletal muscles. It
is not exact number since
some muscles
(palmarislongus)are not
present in all human being.
A pair of lungs and the
passage leading into and out
of the lungs i.e. nose,
pharynx, larynx, trachea,
bronchi.
i) Provides structural
framework for all systems and
along with muscle muscles it
enables mobility.
2
3
Skeletal
System(Fig 11)
Muscular
System(Fig.12)
Respiratory
system
(Fig.13)
ii) Protects and supports body
organs
iii) The marrow in bone is the
site of blood cell formation
iv)Stores minerals
i) Movement by contractions.
ii) Maintains posture.
iii) Produces heat.
iv) Allows manipulation of the
environment, locomotion, and
facial expression.
i) To supply oxygen
ii) To remove carbon dioxide
4
Cardiovascular It is a part of circulatory
System
system. It consists of heart,
blood vessels and blood.
(Fig.14)
i) Supplies oxygen and
nutrients to cells.
ii) Carries carbon dioxide and
waste products from cells.
iii) Maintains acid base
balance of the body.
5
Lymphatic
system
(Fig.15)
6
Digestive
System(Fig.16)
7
Endocrine
System(Fig.17)
8
Excretory
System(Fig.18)
Lymphatic system is also a
part of circulatory system. It is
an open system and consists
of lymphatic vessels that go
towards heart (afferent),
lymph nodes, thymus gland,
and Spleen.
Oral cavity, tongue, teeth,
esophagus, stomach, small
intestine, large intestine,
rectum, anus, and accessory
glands i.e. salivary glands,
pancreas, gall bladder and
liver.
All the endocrine glands of
the body which produce
hormones and similar
substances.
Drains lymph fluid (about 3 L
in a day) to support the
cardiovascular system. This
system is also main source of
lymphocytes and provides
immunity to the body.
Composed of kidneys,
ureters, urinary
bladder,urethra, liver, and
sweat glands.
To eliminate the waste
products
i) Digestion and absorption of
food.
ii) Eliminates indigestible
foodstuffs as feces
Hormones are responsible for
chemical regulation of all body
functions.
Regulate the fluid and
electrolyte balance.
Maintain acid base balance of
the body.
9
Reproductive
System(Fig.19)
In male it consists of testis,
seminal vesicles, penis, and
urethra;in females consist of
ovaries, Fallopian tubes,
i) Production of offspring
ii) Testes produce sperm and
male sex hormones
uterus, vagina and vulva.
Mammary glands are not
considered as organ of the
reproductive system,
although it has relation with
reproductive system.
iii) Ducts and glands deliver
sperm to the female
reproductive tract
iv) Ovaries produce eggs and
female sex hormones
v) Remaining structures serve
as sites for fertilization and
development of the fetus.
10
11
Integumentary
system(Fig. 20)
Special senses
(Fig. 21)
It forms the external body
covering. It is Composed of
the skin, sweat glands, oil
glands, hair, and nails.
i) Protects deep tissues from
injury
Consist of Eye, ear and
vestibular organ, Taste buds
and smell organs.
Eye gives power of vision.
ii) Synthesizes vitamin D
Ear provides hearing sense
and vestibular organ helps in
maintaining balance.
Taste buds on Tongue
produce taste for foods.
Smell organs in nose helps in
perception of flavourand
fragrance of material.
12
Nervous
system(Fig 22)
Consist of Cerebrum,
cerebellum, brainstem, spinal
cord and peripheral nerves
Control all body functions.
Credits and References:
We express our deep gratitude to the persons who has helped in this video production.
They are
Mr. AbhijitBiswas
Mr. Triloki Prasad
Ms. JayshreeSen
Mr. Siddhartha Sen
Mr. Soumendra Manna
We also gratefully acknowledge the contributors in the following websites for giving the
pictures under Creative Commons license.
1. http://commons.wikimedia.org/wiki/File:3492769920_f48c41bdc8_bDissection19.jpg
Otis Historical Archives of “National Museum of Health & Medicine” (OTIS Archive 1)
2. http://2012books.lardbucket.org/books/introduction-to-chemistry-general-organic-andbiological/index.html
3. http://en.wikipedia.org/wiki/Epithelium#/media/File:Cheekcells_stained.jpg
4. http://commons.wikimedia.org/wiki/File:Gray1133.png
5. http://commons.wikimedia.org/wiki/File:Normal_gastric_mucosa_intermed_mag.jpg
6. http://commons.wikimedia.org/wiki/File:Corpora_amylacea_intermed_mag.jpg
7. http://commons.wikimedia.org/wiki/File:414_Skeletal_Smooth_Cardiac.jpg
8. http://teaching.ncl.ac.uk/bms/wiki/index.php/File:Lrg-1348-skeletal_muscle.jpg
9. http://commons.wikimedia.org/wiki/File:Blood_smear.jpg
10. http://commons.wikimedia.org/wiki/File:Gray73.png
11. http://commons.wikimedia.org/wiki/File:Grey_matter_and white_matter
intermed_mag.jpg
12. http://en.wikipedia.org/wiki/Neuron#/media/File:Neuron_Hand-tuned.svg
13. http://2012books.lardbucket.org/books/introduction-to-chemistry-general-organic-andbiological/index.html (accessed on 25/01/2015 at 8:45 am)
14. http://commons.wikimedia.org/wiki/User:LadyofHats/gallery2#/media/
File:Human_healthy_pumping_heart_en.svg Accessed on 11.03.2015
15. http://commons.wikimedia.org/wiki/File:Hooke-microscope.png Accessed on
03.03.2015
16. http://commons.wikimedia.org/wiki/File:3492769920_f48c41bdc8_bDissection19.jpg
Accessed on 03.03.2015
17. http://commons.wikimedia.org/wiki/File:Muscles_anterior_labeled.png
andHäggström, Mikael. "Medical gallery of Mikael Häggström 2014". Wikiversity
Journal of Medicine 1 (2). DOI:10.15347/wjm/2014.008. ISSN20018762)
18. http://commons.wikimedia.org/wiki/File:Respiratory_system_complete_en.svg
19. http://commons.wikimedia.org/wiki/File:Human_healthy_pumping_heart_en.svg
20. http://en.wikiversity.org/wiki/Blausen_gallery_2014#/media/File:Blausen_0623_Lymp
hatic System_Female.png
20. http://commons.wikimedia.org/wiki/File:Digestive_system_diagram_en.svg
21. http://commons.wikimedia.org/wiki/File:Endocrine_Alimentary_system_en.svg
22. http://commons.wikimedia.org/wiki/File:Endocrine_reproductive_system_en.svg
23. http://en.wikibooks.org/wiki/Human_Physiology/The_male_reproductive_system
24. http://commons.wikimedia.org/wiki/File:Female_reproductive_system_lateral.png
25. http://commons.wikimedia.org/wiki/File:Gray940.png
26. http://commons.wikimedia.org/wiki/File:Anatomy_of_the_Human_Ear.svg
27. http://commons.wikimedia.org/wiki/File:Eyesection.svg
28. http://commons.wikimedia.org/wiki/File:TE-Nervous_system_diagram.svg
References:
1. Wang, Z. M., Pierson Jr., R.N. andHeymsfield, S.B. (1992) The Five level model:
A new approach to organizing body-composition research. Am J ClinNutr, 56, 1928.
2. Schwann, T. and Schleyden, M.J. (1847) Microscopical researches into the
accordance in the structure and growth of animals and plants. London: Printed for
the Sydenham Society.
3. David W. Ball, John W. Hill, Rhonda J. Scott (no publication date available)
Introduction to Chemistry: General, Organic, and Biological(v. 1.0) (Publisher
detail not available) Gray, Henry & Carter, Henry Vandyke (1858), Anatomy
Descriptive and Surgical, London: John W. Parker and Son.
4. OpenStax College, Anatomy & Physiology. OpenStax College. 25 April 2013.
<http://cnx.org/content/col11496/latest/>
Summary
Human body is composed of large number of elements. Some of them are found in large
quantity whereas many are in very low quantity (called as trace elements). Human body
is categorized in different organizational levels such as elemental, molecular, cellular,
tissue, organ and system. An ideal cell usually contains sub-cellular structures (called
organelles) like nucleus, cell membrane, cytoplasm, mitochondria, Golgi body,
endoplasmic reticulum, centriole, ribosome, and vacuole. Barring a few exceptions all the
cells contain a nucleus. Skeletal muscle cells contain more than one nuclei and matured
red blood corpuscle has no nucleus. Tissues are formed by group of cells performing a
set of specific function. Four types of tissue are found in the human body as epithelial,
connective, muscular and nervous. These tissues form organs and finally group of
organs form systems. The human body is thus an extremely complex system in respect
to structure and functional mechanism. There are 22 structural systems present in the
body. They are skeletal,muscular, respiratory, cardiovascular, lymphatic, digestive,
endocrine, excretory, reproductive, integumentary, nervous system and special senses.
Special senses include five types of sensory organs vision, hearing, touch, smell, and
taste.
Figure 11: Some components of Skeletal system (modified from Gray & Carter, 1858)
Front side
Back side
Figure 12: Superficial muscles in human body
(Source: http://commons.wikimedia.org/wiki/File:Muscles_anterior_labeled.png and
Häggström, Mikael. "Medical gallery of Mikael Häggström 2014". Wikiversity Journal of
Medicine 1 (2). DOI:10.15347/wjm/2014.008. ISSN20018762)
Figure 13: Components of respiratory system.
(Source:http://commons.wikimedia.org/wiki/File:Respiratory_system_complete_en.svg)
Figure 14: Healthy pumping heart in systole & diastole.
(Source:http://commons.wikimedia.org/wiki/File:Human_healthy_pumping_heart_en.svg)
Figure 15:Lymphatic system of the body. (Source:
http://en.wikiversity.org/wiki/Blausen_gallery_2014#/media/File:Blausen_0623_Lymphati
cSystem_Female.png)
Figure 16: Digestive system in man
(Source:http://commons.wikimedia.org/wiki/File:Digestive_system_diagram_en.svg)
Figure 17a: Endocrine system of the body
(Source:http://commons.wikimedia.org/wiki/File:Endocrine_caclcium_en.svg)
Figure 17b: Endocrine system of the body
(Source:http://commons.wikimedia.org/wiki/File:Endocrine_central_nervous_en.svg)
Figure 17c: Endocrine system of the body
(Source: http://commons.wikimedia.org/wiki/File:Endocrine_Alimentary_system_en.svg)
Figure 17d: Endocrine system of the body
(Source:http://commons.wikimedia.org/wiki/File:Endocrine_reproductive_system_en.svg)
Figure 18: Excretory system (Adopted from Gray & Carter, 1858)
a)
b)
Figure: 19 Human reproductive systema) Male and b) female (Source:
http://en.wikibooks.org/wiki/Human_Physiology/The_male_reproductive_systemand
http://commons.wikimedia.org/wiki/File:Female_reproductive_system_lateral.png)
Figure 20: Diagram of histological section of skin (Source:
http://commons.wikimedia.org/wiki/File:Gray940.png)
Figure 21a): Diagrammatic view of Ear
(Source: http://commons.wikimedia.org/wiki/File:Anatomy_of_the_Human_Ear.svg)
Figure 21b): Diagrammatic view of Eye.
(Source: http://commons.wikimedia.org/wiki/File:Eyesection.svg)
Figure 22: Nervous system of the body
(Source: http://commons.wikimedia.org/wiki/File:TE-Nervous_system_diagram.svg)
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