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Summary

Biology Class 03

## EXCRETORY SYSTEM:

- Waste removal and regulation of water.
- Urine (urea 2.5%, other waste 2.5%, water 95%).
- Kidney stone- calcium oxalate.

## CIRCULATORY SYSTEM (05:10 PM)

- System of transportation in the body (heart, blood, blood vessels).
- **Heart:**
- 4 chambers of the heart.
- Upper chamber- auricles/atrium (right auricles and left auricles).
- Lower chamber- ventricle (right ventricle and left ventricle).
- **Blood vessels:**
- Arteries are those blood vessels that take blood away from the heart.
- Veins are those blood vessels that take blood towards the heart.
- Veeins are thin-walled and arteries are thick walls.
- Veins are superficial and bluish-green.
- Arteries are deep-seated and reddish.
- **Double circulation in the Heart:**
- Right ventricle-lungs-left auricle- left ventricle- body except for lung-right auricle-right ventricle.
- \* Please refer to the diagram of Double circulation in the Heart, as shown on the whiteboard.
- Arteries always carry oxygenated blood except for the pulmonary artery.
- Veins carry deoxygenated blood except for pulmonary veins.

## GLANDS (05:27 PM)

- Exocrine gland and endocrine gland.
- Exocrine glands have ducts/tubes to connect the body organ, for example, the liver.
- Endocrine glands do not have ducts/tubes and these gland release chemicals called hormones directly into the blood.
- **Endocrine system:**
- It is meant for internal communication and regulation of the Human body.
- Hormones are secretions of endocrine glands that do not have ducts and secret directly into the blood to be transported to distantly located target organs.
- **Hypothalamus (05:41 PM)**
- Releasing hormone- it stimulates the pituitary gland to release its secretion.
- Inhibiting hormone- It inhibits the pituitary glands from releasing its secretion.
- **Pituitary Gland:**
- **Anterior pituitary-**
- Thyroid-stimulating Hormone (TSH) stimulates the thyroid gland to release its secretion.
- Prolactin- this is for the formation of milk.
- Adrenocorticotropic Hormone (ACTH) stimulates the adrenal gland to release its secretions.
- Follicle Stimulating Hormone (FSH) helps in the maturation of eggs and the formation of sperm.
- Growth Hormone- is for the growth and development of the body.
- Luteinizing Hormone (LH) stimulates the gonads or sex organs to produce the sex hormones.
- **Posterior Pitituary (05:53 PM)**
- Anti Diuretic Hormone (ADH or Vasopressin)- reabsorption of water and mineral from the kidney.
- Oxytocin is released during childhood.
- **Thyroid  Gland and Parathyroid Gland (05:59 PM)**
- Thyroxine/Thyroid Hormone helps in the metabolism of carbohydrates, proteins, and fats.
- Parathyroid Hormone is involved in the metabolism of calcium and phosphate in the body.
- High amount of parathyroid hormone  (high calcium and low phosphorous).
- Low amount of parathyroid hormone  (low calcium and high phosphorous).

## ADRENAL GLAND (06:04 PM)

- **Adrenal Medulla:**
- Adrenaline and nor-adrenaline are the emergency hormone of the body, which are released in situations of fear, being frightened, anxious, or extreme excitement.
- **Adrenal cortex:**
- Mineralocorticoid regulates the balance of water and minerals in the body.
- It helps to maintain blood pressure in the body.
- Glucocorticoids are involved in carbohydrate metabolism.

## PANCREAS (06:11 PM)

- Insulin reduces blood glucose levels.
- Glucagon increases blood glucose levels.
- Nephrons- the basic unit of the kidney.

## HEALTH (06:44 PM)

- Health is the complete physical, mental, and social well-being of a person and not merely the absence of diseases.
- Disease (congenital disease and acquired disease).
- Acquired diseases- communicable diseases/ infectious diseases and noncommunicable/ non-infectious diseases.
- **Congenital disease** is any abnormality in the structure or function of a person which is present right from the time of birth.
- For example genetic diseases like Down syndrome, and congenital heart disease.
- **Acquired disease** is any disease that is not present at the time of birth but develops at a later stage of the life of an organism.
- Communicable/ infectious disease occurs because of the disease-causing organism called pathogens.
- For example- malaria, dengue, covid, etc.
- Non-communicable/ non-infectious diseases are not caused by a pathogen but by lifestyle or environmental factors.
- For example- cardiovascular disease, respiratory disease (asthma), deficiency disease (vitamins and minerals- rickets), mental disorder(depression, bipolar), environmental disease (Minamata disease- mercury), occupational disease (silicosis), cancer.

## COMMUNICABLE DISEASES (07:15 PM)

- Modes of transmission:
- Air- covid, TB.
- Water- cholera.
- Food- typhoid, amoebiasis.
- Soil- hookworm.
- Blood and body fluid- AIDS.
- Direct contact- covid-19, common cold.
- Fomite- non-living things- chicken pox.
- Zoonotic- animal- swine flu, rabies.
- Vector- mechanical vector versus biological vector.
- Vectors are organisms that do not cause the disease itself but spread the infection by taking pathogens from one organism to another.
- Mechanical vectors carry the pathogen on the surface of their body and biological vectors carry the pathogen within their body.

## HELMINTHIC DISEASE (07:33 PM)

- Worm infection (roundworms, flatworms).
- Ascariasis by ascaris, a roundworm.
- Taeniasis by taenia solium, a flatworm.
- Lymphatic filariasis- elephantiasis.
- Hookworm infection, a roundworm.

## PROTOZOAN DISEASES (07:41 PM)

- Example- Amoebiasis, Giardiasis, and Malaria.
- Malaria- Plasmodium( Vivax, and Falciparum).
- Vector- female Anopheles mosquitos.
- **Malaria Transmission Cycle:**
- First infected mosquito (Plasmodium in female Anopheles mosquitos).
- First infected person (Plasmodium in the blood).
- Infected liver cells (growth of plasmodium in the liver).
- Infected Red blood cells (increase in number in Plasmodium- RBCs burst).
- Second infected mosquito (Plasmodium in the blood).
- Second infected person.
- Reproduction-Asexual (one parent) and sexual (male and female).

## FUNGAL DISEASES (07:56 PM)

- Ringworm.
- Athletes' foot.
- Candidiasis- Candida Albicans.
- **Please refer to Ncert:**
- Class 7- Chapter 7.
- Class 8- Chapters 2, and Chapter 7.
- Class 11- chapter 19.

## NEXT CLASS TOPIC:  Health and Immunity.