Quick Revision Notes & Formula Sheet

Class 7 Science: Transportation in Animals and Plants

MP Board Education

---

### Concept 1: Circulatory System in Animals (जंतुओं में परिसंचरण तंत्र)

The circulatory system is responsible for the transport of oxygen, nutrients, waste products, and other substances throughout the body.

• Blood (रक्त): A fluid that flows in blood vessels. It transports substances like digested food from the small intestine to the other parts of the body.
• Components of Blood:
  1. Plasma (प्लाज्मा): The liquid part of blood.
  2. Red Blood Cells / RBC (लाल रक्त कोशिकाएं): Contain a red pigment called haemoglobin (हीमोग्लोबिन) which binds with oxygen and transports it to all the parts of the body.
  3. White Blood Cells / WBC (श्वेत रक्त कोशिकाएं): Fight against germs that enter our body.
  4. Platelets (प्लेटलेट्स): Help in the clotting of blood (रक्त का थक्का जमना) to prevent excessive bleeding when injured.

---

### Key Formulas & Measurement Standards

• Normal Heart Rate: 72 to 80 beats per minute (असामान्य रूप से आराम करते समय हृदय स्पंदन).
• Normal Blood Pressure (Human): Roughly 120/80 mmHg (Systolic/Diastolic).
• Pulse Rate: The thumping felt due to the throbbing of blood in the arteries is equal to the number of heart beats per minute.

---

### Concept 2: Blood Vessels (रक्त वाहिनियाँ)

There are three main types of blood vessels in the human body:

1. Arteries (धमनियाँ):
   • Carry oxygen-rich blood (शुद्ध रक्त) from the heart to all parts of the body.
   • Have thick, elastic walls because the blood flows at high pressure.
   • Exception: Pulmonary artery carries carbon dioxide-rich blood from the heart to the lungs.
2. Veins (शिराएँ):
   • Carry carbon-rich blood (अशुद्ध रक्त) from all parts of the body back to the heart.
   • Have thin walls and valves to ensure blood flows only towards the heart.
   • Exception: Pulmonary vein carries oxygen-rich blood from the lungs to the heart.
3. Capillaries (केशिकाएँ):
   • Extremely thin blood vessels that join arteries to veins. Exchange of substances takes place through them.

---

### Concept 3: The Human Heart (मानव हृदय)

• Definition: The heart is an organ that beats continuously to act as a pump for the transport of blood.
• Location: Located in the chest cavity with its tip slightly tilted towards the left.
• Chambers of the Heart: The heart is divided into four chambers to prevent mixing of oxygen-rich and carbon dioxide-rich blood:
  • Upper chambers: Right Atrium and Left Atrium (दायाँ और बायाँ अलिंद).
  • Lower chambers: Right Ventricle and Left Ventricle (दायाँ और बायाँ निलय).
• Heartbeat: The walls of the chambers made of muscles contract and relax rhythmically. This rhythmic contraction followed by its relaxation constitutes a heartbeat.

---

### Concept 4: Excretion in Animals (जंतुओं में उत्सर्जन)

• Excretion (उत्सर्जन): The process of removal of wastes produced in the cells of the living organisms.
• Excretory System in Humans:
  • Consists of a pair of kidneys (वृक्क), a pair of ureters (मूत्रवाहिनी), a urinary bladder (मूत्राशय), and a urethra (मूत्रमार्ग).
  • Kidneys: Filter the blood to remove waste products. The filtered waste is dissolved in water and removed as urine (मूत्र).
• Excretory Products based on Animals:
  • Humans/Mammals: Excrete Urea (यूरिया).
  • Fish/Aquatic animals: Excrete Ammonia (अमोनिया) which directly dissolves in water.
  • Birds, Insects, Lizards: Excrete a semi-solid, white coloured compound called Uric Acid (यूरिक अम्ल).
• Sweat (पसीना): Contains water and salts to help cool the body and remove excess waste.

---

### Concept 5: Transportation in Plants (पादपों में परिवहन)

Plants absorb water and minerals from the soil and transport them to the leaves, which prepare food using sunlight (photosynthesis).

• Vascular Tissues (संवहनीय ऊतक): Plants have pipe-like vessels to transport substances. There are two types:
  1. Xylem (जाइलम):
     • Transports water and minerals (जल और खनिज लवण) from the roots to the leaves and other parts of the plant.
     • Forms a continuous network of channels.
  2. Phloem (फ्लोएम):
     • Transports food (भोजन/खाद्य पदार्थ) prepared by the leaves to all other parts of the plant.
• Transpiration (वाष्पोसर्जन):
  • The process by which plants lose water in the form of water vapour through tiny pores called stomata (रंध्र) present on the leaves.
  • Functions:
    • Creates a suction pull that draws water up from the roots to great heights.
    • Helps in cooling the plant.