Animal Tissues and Human Blood

Animal Tissues and Human Blood

Animal Tissues

The animal tissues can be divided into the following categories –

1. Epithelial Tissue

2. Connective Tissue

3. Muscular Tissue

4. Nervous Tissue

1. Epithelial Tissue

• Epithelial tissue covers the external surface of the body and the internal free surface of many organs.

• Epithelial cells are arranged very close to each other.

• There are no blood vessels supplying nourishment to epithelial cells.

• They receive nourishment from underlying connective tissue.

• The principle functions of epithelial tissues are covering and lining on free surfaces.

Examples: Skin, intestine, gland, hollow organs like fallopian tube, nasal passages, bronchioles, trachea etc.

2. Connective Tissue

• These tissues connect and bind different tissues or organs.

• It provides the structural frameworkand mechanical support to the body.

• It play important role in body as defense tissue, repair, fat storage, etc.

Examples: Adipose tissue found beneath the skin. A ligament is made up of fibrous connective tissue. Cartilage, bone and blood are connective tissues.

Additional Notes:

• Ligament: It is fibrous tissue which connects bone to bone.

• Tendon: A flexible, inelastic cord of strong fibrous tissue which attaches muscles to bone.

3. Muscular Tissue

• This is also known as contractile tissue. All the muscles of the body are made up of this tissue.

Types of Muscle Tissue:

(a) Unstriped

(b) Striped

(c) Cardiac

(a) Unstriped Muscles

• This muscle tissue is found in the walls of those parts which are not controlled by will.

• These are called involuntary muscles, like the alimentary canal, rectum, ureter, and Blood vessels.

• Unstriped muscles control the motions of all those organs that move on their own.

Note: Muscular tissues are responsible for the movement in our body.

(b) Striped Muscles

• These muscles are found in the parts of the body that move voluntary.

• Normally one or both the end of these muscles connect with bones by tendon.

(c) Cardiac Muscles

• These muscles are found only in the wall of the heart.

• The contraction and expansion of the heart is due to these muscles that move throughout the life without fail.

Important Facts About Muscular Tissue

• There are over 650 skeletal muscles in the human body.

• The largest muscle of the human body is Gluteus Maximus (muscle of the hip).

• The smallest muscle of the human body is Stapedius.

• On the basis of weight, the strongest muscle is found in the jaw.

• Muscles contain special protein called contractile protein which help in muscle movement.

Additional Notes

• In vertebrates inside the cell and tissues there is a low concentration of K⁺ ion and high concentration of Na⁺ ion.

• Ureters, Iris of eye & Brenchi of lung are made up of smooth muscles.

• Unstriped muscles are also known as smooth muscles.

• Arrector pili are the muscle found in skin which make hair on the skin stand up straight when we are cold or frightened.

• Ciliated epithelium line the inner surface of fallopian tubes, bronchioles and bronchi.

4. Nervous Tissue

• This tissue is also called sensory tissue.

• The nervous system of the organisms is made up of these tissues.

This is made up of two specific cells –

(a) Nerve cell or Neurons

(b) Neurogilia

Function:

Nervous tissue control all the voluntary and involuntary activities of the body.

Human Blood

Blood is a type of fluid connective tissue.

• The quantity of blood in the human’s body is approximately 7 to 8% of the total weight of an adult.

• This is a dissolution of base whose pH value is 7.4.

• There is an average of 5–6 litres of blood in the human body.

• Females contain 4 to 5 litres of blood, less in comparison to males. This difference is due to the size of the body.

• The spleen acts as a storage organ for blood. It plays an important role in the filtration of blood as part of the immune system.

Parts of Blood

Blood consists of two parts –

(A) Plasma

(B) Blood Corpuscles

(A) Plasma

This is the liquid part of blood. 60% of the blood is plasma.

Composition:

• 90% water

• 7% protein

• 0.9% salt

• 0.1% glucose

  • Remaining substances are in very low quantity.

Function of Plasma:

• Transportation of digested food, hormones, excretory product etc. from one part of the body to another part.

Serum:

• When Fibrinogen and protein are extracted out of plasma, the remaining plasma is called serum.

(B) Blood Corpuscles

This is the remaining 40% part of the blood.

It is divided into three parts –

1. Red Blood Corpuscles / Red Blood Cells (RBCs)

2. White Blood Corpuscles / White Blood Cells (WBCs)

3. Blood Platelets

1. Red Blood Corpuscles (RBC)

• Red Blood Corpuscles (RBC) / Red Blood Cells of a mammal are biconcave.

• There is no nucleus. (Exception – camel and Lama.)

• New RBC is formed in Red Bone Marrow.

  • (At the embryonic stage its formation takes place in the liver.)

• Its life span is from 20 days to 120 days.

• Its destruction takes place in liver and spleen. Therefore, liver is called grave of RBC.

• It contains hemoglobin, in which haeme is an iron-containing compound, and due to this, the colour of blood is red.

• Globin is a proteinous compound. With haeme it is capable of combining with oxygen and carbon dioxide.

• The iron compound found in hemoglobin is called hamatin.

• Normal range of hemoglobin content of an adult man is 17.5 gm/100 ml of blood.

Functions:

• The main function of RBC is to carry oxygen from the lungs to all cells of the body and bring back carbon dioxide.

Additional Notes:

• Anaemia disease is caused due to deficiency of hemoglobin.

• At the time of sleeping RBC reduces by 5%.

• People who are at the height of 4200 meters have 30% more RBC.

• Number of RBC is measured by an instrument called hemocytometer.

• In adult man its number ranges from 4 to 5 million per cubic millimeter.

2. White Blood Corpuscles (WBC) or Leucocytes

• Its shape is similar to Amoeba.

• Its formation takes place in Bone marrow, lymph node, and sometimes in liver and spleen.

• Its life span is from 13 to 20 days.

• Normal range: 4,000 to 11,000 per cubic millimeter.

• Nucleus is present in WBC.

• Its main function is to protect the body from disease.

• The ratio of RBC and WBC is 600 : 1.

Types of WBC:

• About 60 to 70% of WBC is made up of neutrophile corpuscles which help in engulfing disease-causing microorganisms and bacteria.

• Lymphocytes are a type of Leucocytes formed in bone marrow.

• ‘B’ and ‘T’ lymphocytes protect the body from diseases caused by pathogens.

3. Blood Platelets or Thrombocytes

• It is found only in the blood of humans and other mammals.

• There is no nucleus in it.

• Its formation takes place in Bone marrow.

• Its life span is from 8 to 9 days.

• Normal platelet count: 1,50,000 to 4,50,000 per cubic milliliter of blood.

• Its main function is to help in clotting of blood.

• In dengue fever, the number of platelets is reduced.

Functions of Blood

1. To control the temperature of the body and to protect the body from diseases.

   • Normal temperature of the human body is 98.4°F (37°C).

2. Clotting of blood is known as Coagulation.

3. Transportation of O₂, CO₂, digested food, hormones, excretory material etc.

4. To help in establishing coordination among different body parts.

Clotting of Blood

Three important reactions during the clotting of blood –

1. Thromboplastin + Prothrombin + Calcium = Thrombin

2. Thrombin + Fibrinogen = Fibrin

3. Fibrin + Blood Corpuscles = Clot

The formation of Prothrombin and Fibrinogen of the blood plasma takes place with the help of Vitamin K.

The compulsory protein for making clots of blood is Fibrinogen.

Blood Group of Human

• Blood group was discovered by Landsteiner in 1900.

• He was awarded the Nobel Prize in 1930.

• The main reason behind the difference in human blood is the glycoprotein found in Red Blood Corpuscles called antigen.

Types of Antigen:

• Antigen A

• Antigen B

Four Groups of Blood in Humans

Explanation: On the basis of the presence of Antigen or Glycoprotein, there are four groups of blood in humans:

(a) Contains Antigen A – Blood Group A

(b) Contains Antigen B – Blood Group B

(c) Contains Both Antigens A and B – Blood Group AB

(d) Contains Neither Antigen – Blood Group O

Blood Transfusion

• Antigen ‘A’ and antibody ‘a’, and Antigen ‘B’ and antibody ‘b’ cannot live together.

• If they mix, they become sticky and spoil the blood — this is called agglutination of blood.

• Therefore, in blood transfusion, adjustment of Antigen and Antibody should be done carefully to avoid agglutination.

  • Universal Donor: Blood Group O (contains no antigen)

  • Universal Receptor: Blood Group AB (contains no antibody)

Rh Factor

• In 1940, Landsteiner and Wiener discovered a different type of antigen in blood.

• They discovered it in the Rhesus monkey; therefore, it is called the Rh-factor.

• If the blood contains Rh antigen → Rh-positive (Rh⁺)

• If not → Rh-negative (Rh⁻)

During transfusion:

• Rh⁺ blood should be given to Rh⁺, and Rh⁻ blood to Rh⁻ only.

• If Rh⁺ blood is transferred to an Rh⁻ person once, there may not be a visible reaction. But on repetition, due to agglutination, the Rh⁻ person may die.

Therefore, during transfusion, blood must be compatible not only in blood type but also in Rh factor.

Erythroblastosis Foetalis

If the father’s blood is Rh⁺ and the mother’s blood is Rh⁻, then the child to be born may die during pregnancy or shortly after birth. (This usually happens in the case of the second issue.)

Possible Blood Group of the Child

Haemolymph

• Body fluid of arthropoda is colourless and made of plasma and haemocytes.

• It does not contain any respiratory pigment.

Example: Cockroach.