The Bio Brief

TRANSPORTATION IN HUMANS

 Blood

• Blood is a fluid connective tissue
• It has plasma and cells

Plasma carries:

• Digested food
• Carbon dioxide
• Nitrogenous wastes
• Salts

Blood cells:

• Red Blood Cells (RBCs): carry oxygen
• White Blood Cells (WBCs): fight diseases
• Platelets: help in blood clotting

Heart – The Pump

• Heart is a muscular organ, about the size of a fist
• It pumps blood to all parts of the body
• It has 4 chambers:

Left Atrium → Left Ventricle

Right Atrium → Right Ventricle

 Working of the Heart (Flow Chart)

Body → Right Atrium → Right Ventricle → Lungs

Lungs → Left Atrium → Left Ventricle → Body

Key Points:

• Right side: Deoxygenated blood (CO₂-rich)
• Left side: Oxygenated blood (O₂-rich)
• Valves prevent backward flow of blood
• Ventricles have thicker walls than atria

Double Circulation

• Blood passes through the heart twice in one cycle
• Seen in birds and mammals

Heart Types:

Animal	Heart Chambers
Fish	2 chambers
Frog/Reptiles	3 chambers
Birds/Mammals	4 chambers

Blood Vessels

Arteries

• Carry blood away from heart
• Thick and elastic walls
• High blood pressure

 Veins

• Carry blood towards heart
• Thin walls
• Have valves

 Capillaries

• Very thin (one-cell thick)
• Exchange of gases, food, and wastes

Artery → Capillaries → Vein

 Platelets – Repair System

• Help in blood clotting
• Prevent excess blood loss during injury

 Lymph

• Colourless fluid
• Formed from leaked plasma
• Functions:
  • Returns extra fluid to blood
  • Transports fats from intestine
  • Helps in immunity

TRANSPORTATION IN PLANTS

Plants need transport for:

• Water
• Minerals
• Food (photosynthesis products)

They use vascular tissues:

Xylem → Water & Minerals

Phloem → Food

 Transport of Water (Xylem)

Xylem carries:

• Water
• Minerals

Process:

1. Roots absorb minerals
2. Water enters roots by osmosis
3. Water moves upward due to:
   • Root pressure
   • Transpiration pull

Transpiration

• Loss of water vapour from leaves
• Creates suction force
• Helps:
  • Upward movement of water
  • Cooling of plant

Soil → Roots → Stem → Leaves

Transport of Food (Phloem)

• Food made in leaves (photosynthesis)
• Transported to:
  • Roots
  • Fruits
  • Seeds
  • Growing parts

This process is called Translocation

Important Points:

• Occurs in sieve tubes
• Needs energy (ATP)
• Can move upward and downward

Flow Chart:

Leaves → Phloem → Storage/Growing Parts

Quick Comparison Table

Feature	Xylem	Phloem
Transports	Water & minerals	Food
Direction	One direction (upward)	Both directions
Energy	No	Yes (ATP)

 KEY POINTS

• Humans use heart + blood vessels
• Plants use xylem and phloem
• Transportation is essential for survival