TYPES OF DISEASES Unit - VIII Lesson XVI ......The infectious diseases are often transmitted by pathogens. Pathogens can be of different types. They can be either bacteria or virus

1www.nationaldefenceinstitute.in

Unit - VIIILesson XV - ANATOMY AND PHYSIOLOGY OF HUMAN BODY

Lesson XVI - CLASSIFICATION OF DISEASES – TYPES OF DISEASES

15.HUMAN BODY

ANATOMY AND PHYSIOLOGY OF HUMAN BODY


Index▷ Introduction▷ Respiratory System▷ Digestive System▷ Excretory System▷ Cardiovascular or Circulatory System▷ Endocrine System▷ Nervous System▷ Musculoskeletal System▷ Skeletal System▷ Exocrine System▷ Lymphatic System▷ Reproductive System


Introduction:● We can define body systems as groups of organs and

tissues that work together to perform important jobs for the body.

● There are some organs in our body which are part of more than one body system as they serve more than one function.


Respiratory System

5

Respiratory System:● It executes the gas exchange between cells and the

environment and includes trachea and lungs. ● The respiratory system takes oxygen from the

environment and converts it into a form that cells can use.

● In humans, it means that our lungs take in oxygen, and rapidly diffuse it into the blood.

● The lungs accomplish this function by passing large amounts of blood over gas exchange membranes, the body’s whole blood volume passes over these membranes about once per minute.

● Without oxygen to fuel cellular respiration, cells begin to die within minutes.


Lungs:● Lungs are the main respiratory organ. The trachea,

commonly called windpipe . ● The trachea divides into right and left bronchi and

enter into the lungs. ● They divide further and ends in small air sacs called

alveoli. ● The lungs are covered by a double layered pleura . ● Diffusion of gases (O2 and CO2) occurs across the

alveolar membrane


Respiration:

External Respiration:

Intake of O2 from the air and releasing of CO2 from the lungs occurs through nostrils.

Internal Respiration:

Taking in of oxygen and giving out CO2.

The circulatory system transports O2 and CO2 to and from all parts of the body.

Hemoglobin in the red blood cells (RBCs) transport O2 and CO2.

Cellular Respiration:

Cells take in O2 and release CO2.

8

Digestive System

9

Digestive System: ● This system intakes food, breaks it down into usable

nutrients and excretes solid waste products. ● It includes the mouth, esophagus, stomach, and

intestines. ● One of the most important purposes of food is to

serve as cellular fuel. ● Carbohydrates, proteins, and fats can all be used by

our cells as sources of the energy that they need to stay alive.


Digestive System: ● This system is involved in the conversion of complex

food substances into simple forms and absorption of digested food.

● The digestive glands associated with the alimentary canal are salivary glands, liver, and pancreas.

● They secrete enzymes which help in the process of digestion of food in the digestive tract or alimentary canal.

● The alimentary canal is about 9 meters long. Stomach is a major organ for digestion of food materials.

● Absorption of digested food occurs in the small intestine.


Excretory System:

12

Excretory System: ● It cleans dissolved waste products from the blood

and excretes them. ● It includes kidneys and bladder. ● All blood is passed through the kidneys, where

special filters allow dangerous substances to pass out of the bloodstream while keeping helpful substances in.

● The waste liquid that’s filtered out by the kidneys is stored in the bladder until the body expels it.


Organs in the Excretory System: 1. Kidneys:

○ These are bean shaped structures present in the abdominal cavity. The functional units of the kidney are called Nephrons which filter the blood and form the urine.

2. Ureter○ Carries urine from the kidneys to the urinary

bladder.3. Urinary bladder:

○ An expandable muscular sac that retains until urine it is discharged from body.

4. Urethra:○ The tube through which urine is discharged

from the body


Cardiovascular or Circulatory System

15

Cardiovascular or Circulatory System:● This system moves materials between body systems,

including oxygen, nutrients, hormones, and waste products.

● It includes the heart, arteries, and veins. ● This system takes only about a minute to circulate

the whole body’s entire blood volume thus making this a truly high-speed expressway for distributing oxygen, nutrients, messages, and removing waste.


Heart:● The heart is four chambered and is surrounded by a

double layered membrane called pericardium Blood vessels

● Three types of blood vessels are present in the body. They are arteries, veins and capillaries


Blood:● Blood is a fluid connective tissue of red colour

containing plasma and blood cells. ● There are three types of blood cells namely, Red

blood corpuscles (RBCs), White Blood corpuscles (WBCs) and Blood Platelets.

● RBCs are produced in the bone marrow


Endocrine System:

19

Endocrine System:● It also includes hormone-producing tissues such as

a. The pineal gland and pituitary gland in the brain:

b. The thyroid gland; the adrenal glands; the pancreas

c. and the ovaries and testes. ● Some examples of messages sent by the endocrine

system are fight or flight, reproductive signals, hungry or full.


Nervous System:

21

Nervous System:● This system allows perception, emotion, thought,

and rapid response to the environment. It includes the brain and nerves.

● The nervous system allows us to sensory stimuli such as light, sound, smell, and touch from our environment.

● It also allows rapid communication of stimuli within our body, such as sensations of pain, illness, and wellness.

● The nervous system accomplishes all of this using highly specialized cells called neurons, which can transmit signals extremely fast by firing electrochemical potentials.


Brain:

▷ The brain is a complex organ which is placed inside the cranium.

▷ It is protected by a three layered tissue coverings called meninges.

▷ Brain has three regions namely fore brain, midbrain and hindbrain.

▷ It is the controlling centre of the body.

Nervous System:Spinal cord:

▷ It is the extension of medulla oblongata of the hindbrain and is enclosed within the vertebral column.

▷ Spinal cord connects the brain to different part of the body through nerves.

23

Musculoskeletal System:

24

Musculoskeletal System:● It allows the body to move on command. ● There are several main types of muscles in a

mammal: a. smooth muscle b. skeletal muscle and c. cardiac muscle.

● The skeletal system of animals consists of either an endoskeleton, like mammals, or an exoskeleton, seen in insects.

● With the help of endo and exoskeletons, the muscles attach directly to the skeleton, through tendons and other connective tissues.


Types of Muscles:

Skeletal Muscles:

Skeletal muscles of our body are attached to the bones.

They are called Voluntary muscles because they can be controlled by our will.

Example: Muscles of arm.

Smooth Muscles:

Smooth muscles are found in the walls of the digestive tract, urinary bladder, arteries and other internal organs.

They are called ‘Involuntary muscles’ because they are not controlled by our will.

Cardiac Muscles:

The walls of the heart is made up of cardiac muscles.

They are capable of rhythmic, contraction continuously and involuntary in nature

26

Skeletal System:

27

Skeletal System:● The skeletal system consists of bones, cartilages and

joints. ● The adult human skeletal system consists of 206

bones and few cartilages, ligaments and tendons. ● Ligaments help in connecting bone to bone. ● Tendons connect bone to muscle.


Skeletal System:

Skull:

The skull is made up of cranial bones and facial bones. It protects the brain and the structures of the face .

Lower jaw bone is the largest and strongest bone in the human face.

Vertebral Column:

Vertebral column extends from the base of the skull.

It protects the spinal cord. It is formed by a number of serially arranged small bones called vertebrae (singular : vertebra)

Rib cage:

The rib cage is made up of 12 pairs of curved, flat rib bones.

It protects the delicate vital organs such as heart and lungs .

▷ The smallest bone in our body is present inside the ear. It is called Stapes

▷ The longest bone in the body is the thigh bone.

▷ A new born baby has more than 300 bones.

29

IntegumentarySystem or Exocrine System

30

Integumentary System or Exocrine System● This system covers the body and regulates its

exchange with the outside world.● It comprises of skin, hair, nails, sweat, and other

glands which secrete substances onto the skin.


Lymphatic System or Immune System

32

Lymphatic System or Immune System:● This system fights infection and includes lymphatic

vessels which permeate the body. ● Every living thing needs to be able to fight infection.

We have white blood cells that can specially target and destroy invading pathogens.

● These white blood cells are made in our bone marrow and stored in our blood and our lymphatic systems.


Reproductive System:

34

Reproductive System:● This system is related to the production of offspring.

It includes ovaries, uterus, mammary glands (breasts), penis, and testes.

● The reproductive system is not essential to individual survival, but it is essential for the survival of the species. In humans, there are two very different reproductive systems:

a. The Male Reproductive Systemb. The Female Reproductive System

● There are some organs in our body which are part of more than one body system as they serve more than one function.


The Male Reproductive System

The male reproductive system which is concerned primarily with producing sperm and giving the male character to the body such as facial hair, etc.

Reproductive System:The Female Reproductive System

The Female Reproductive System deals with pregnancy, childbirth, and baby care for reproduction to be successful. In addition to that it gives the female characters.

36

15.HUMAN BODY

CLASSIFICATION OF DISEASES – TYPES OF DISEASES


Index

▷ Introduction▷ Types of Diseases▷ Immune System


Introduction:● According to a very broad classification, diseases can

also be classified under the following – physical diseases, mental diseases, infectious diseases, noninfectious diseases, deficiency diseases, inherited diseases, degenerative diseases, social diseases, self-inflicted diseases.

● Depending on certain characteristics, diseases can also be classified as an acute disease where the onset of the disease is sudden, lasts for a short time, with rapid changes and chronic diseases where the effects of the disease can last for months or years.


Types of Diseases:● Even though the types of diseases can be

classified very broadly, the classification of diseases into:

○ Infectious diseases ○ Non-infectious diseases

● Infectious diseases can be easily transmitted from one person to the other while the noninfectious disease cannot be transmitted.


Infectious Diseases:● Any organism or microorganism that causes a disease is called

as a pathogen. ● A specific disease is caused by a specific pathogen.● The infectious diseases are often transmitted by pathogens. ● Pathogens can be of different types. ● They can be either bacteria or virus or fungi or a protozoan or

even a helminth. a. Bacterial diseases are Syphilis, Pneumonia, Tetanus, and

Tuberculosis. b. Viral diseases are Chickenpox, Smallpox, Measles, Polio.c. Fungal infections include Ringworm infection, Athlete’s

foot, Yeast infections etc. d. Malaria is a disease caused by an organism belonging to

Protista. e. Diseases caused by helminths include Ascariasis,

Taeniasis etc.


Infectious Diseases:

42

Typhoid:● It is caused by the bacterium, Salmonella typhi. ● The pathogen enters the body through

contaminated food and water. ● High fever, weakness, stomach pain, headache,

constipation, loss of appetite are the symptoms of this disease.

● The Widal test confirms this disease.


Pneumonia:● It is caused by Streptococcus pneumoniae and

Haemophilus influenzae bacteria. ● This disease affects the lungs. ● The alveoli of the lungs get infected and filled with

fluid, causing respiratory problems. ● This is a disease that is acquired by inhaling the

droplets or aerosols that are released by an infected person.

● The main symptoms include chills, fever, headache, and cough.


Common Cold:● The common cold is generally caused by a group of

viruses called rhinovirus. ● The respiratory passage and the nose are commonly

infected here. ● Nasal congestion, discharge, sore throat, cough,

hoarseness, tiredness, are some of the associated symptoms of common cold, that can last for up to seven days.

● This infection is transmitted when an infected person releases the droplets either through a cough or sneeze.

● These droplets can be either inhaled directly by other people or can be transmitted with the help of contaminated objects.


Malaria:● It is a disease caused by a protozoan called

Plasmodium. ● There are different types of malaria caused by

different types of species of Plasmodium. ● Some of the species are Plasmodium vivax,

Plasmodium malaria, Plasmodium falciparum.● Malignant and fatal malaria is caused by Plasmodium

falciparum. ● The female Anopheles mosquito is the vector that

carries the infectious form of the pathogen into the human body.

● Therefore, the malarial parasite has two hosts, i.e. human and mosquito to complete its life cycle.


Malaria:● When an infected female Anopheles mosquito bites

a human, it transfers the sporozoites of the Plasmodium parasite.

● These parasites multiply in the liver cells and then attack the RBCs, rupturing them.

● When RBCs rupture, they release a toxic substance called hemozoin.

● This toxic substance is responsible for the classic symptoms of malaria – fever associated with chills.

● The spread of the disease can be controlled by killing the vector, mosquito.


Tuberculosis (TB):● Tuberculosis (TB) is a disease caused by bacteria

called Mycobacterium tuberculosis. ● The bacteria usually attack the lungs, but they can

also damage other parts of the body. ● TB spreads through the air when a person with TB of

the lungs or throat coughs, sneezes, or talks. ● If you have been exposed, you should go to your

doctor for tests. ● You are more likely to get TB if you have a weak

immune system. ● Symptoms of TB in the lungs may include:● A bad cough that lasts 3 weeks or longer • Weight

loss • Loss of appetite • Coughing up blood or mucus • Weakness or fatigue • Fever • Night sweats


Amoebiasis:● Entamoeba histolytica causes Amoebiasis. ● It is a protozoan parasite that is present in the large

intestine of a human. ● Amoebiasis is also called as amoebic dysentery. ● This disease is transmitted by house flies that carry

the parasite from the contaminated faeces of an infected person to any food product, thereby contaminating it.

● The symptoms include abdominal pain, cramps, constipation, stools with excess mucous etc.


Ascariasis:● It is a disease that is caused by a helminth, Ascaris

lumbricoides, also called the roundworm. ● It is an intestinal endoparasite found in humans.

Muscular pain, internal bleeding, fever, anaemia, intestinal passage blockage are some symptoms of this disease.

● The infection is spread by contamination of soil, water, plants, etc. as the eggs of the parasite are excreted out through the faecal matter.


Filariasis:● Also called as elephantiasis, this disease is

characterized by the inflammation of the affected organs.

● Even genital organs can get affected by this disease. Wuchereria bancrofti and Wuchereria malayi are the filarial worms that are responsible for causing this disease.

● The female Culex mosquito acts as the vector for transmitting the pathogen.


Fungal Diseases:● Ringworm infection is caused by Fungi. Some of the

Fungi that cause this infection are Microsporum, Trichophyton, and Epidermophyton.

● It is a very common infectious disease that is characterized by intense itching and dry, scaly lesions on the skin, nails, and scalp.

● Moisture and heat are the favourable factors that help the fungi grow.


Preventive Measures:● The different types of diseases, especially, infectious

diseases can be prevented by taking the right measures.

● Personal and public hygiene play an important role here.

● Eradication of vectors that carry the pathogens is also an effective preventive measure.

● Vaccinations also help in tackling many infectious diseases.


Immune System:

54

Immune System:● The immune system of the body is the essential

aspect of our survival. ● If an immune system is absent then the body is very

easily susceptible to infections caused by bacteria, virus, and various other pathogens.

● A significant characteristic feature of this immune system is that it can distinguish between the body tissue and a foreign tissue.

● Even dead and faulty cells can be recognized by the immune system, which is cleared away from time to time by the immune system.


Uniqueness of the Immune System:● The immune system also has a role to play in allergic

reactions, organ transplantation, and autoimmune diseases.

● The human immune system consists of tissues, cells, soluble molecules like antibodies and lymphoid organs.

● The white blood cells called the leukocytes have a significant role as they seek out to destroy the disease-causing organisms.

● These leukocytes are stored in different locations in the body including the spleen, bone marrow, and thymus.

● And therefore these organs are called as the lymphoid organs.

● The leukocytes are also present in the lymph nodes of the body.


Antibody:● An antibody is an immunoglobulin. ● It is a Y shaped molecule which is basically

a protein that is produced by the B cells of the immune system.

● Antibodies are produced in response to the exposure to antigens.

● There are five kinds of antibodies Immunoglobulins M, G, E, D and A.

● An antibody is a serum protein that is generally found in blood.


1. Immunoglobulin A – It protects against gastrointestinal and respiratory problems.2. Immunoglobulin D – It activates the B cell, after an interaction with the antigen. 3. Immunoglobulin E – It controls allergic reactions. 4. Immunoglobulin G – They stimulate phagocytes. 5. Immunoglobulin M – It is the largest antibody and helps in the activation of B cells.

End of Unit-VIII


Documents

TYPES OF DISEASES Unit - VIII Lesson XVI ......The infectious diseases are often transmitted by pathogens. Pathogens can be of different types. They can be either bacteria or virus