Body Systems

Plant and Animal Organ Systems and Their Functions

Levels of Organization in Life

• Cell: Basic unit of life.

• Tissue: Group of cells that work together to perform a specific function.

• Organ: A collection of tissues that perform a specific function or group of functions within an organism.

• Organ System: A group of organs that work together to perform specific functions in the body.

Gas Exchange

Overview

• Importance of Gases: Required for metabolic reactions; involves the use of oxygen and release of carbon dioxide.

Animal Gas Exchange Methods

1. Cell Membrane:

   • Used by unicellular organisms for gas exchange via diffusion (e.g., unicellular alga Ventricaria ventricosa).

   • Flatworms also perform respiration through diffusion across the outer membrane.

2. Body Surface/Skin/Cutaneous Respiration:

   • Gases cross the membrane when dissolved in water (moist environment).

3. Gills:

   • Convoluted outgrowths with blood vessels, either internal or external.

   • Oxygen transfer occurs as water flows over gills.

4. Tracheal Systems:

   • Openings called spiracles allow gas exchange, primarily in insects.

5. Lungs:

   • In-foldings of body wall connect to the environment via respiratory tubes.

Plant Gas Exchange

• Stomata: Main sites for gas exchange in leaves.

  • Each stoma has guard cells that regulate its opening and closing.

• Role of Roots and Stems:

  • Contribute minimally; bark (cork cells) is mostly impermeable but has lenticels for gas exchange.

Transport and Circulation

Animal Transport/Circulation

• Circulatory System: Network of vessels (arteries, veins, capillaries) and a pump (heart) to transport nutrients and gases.

• Closed Circulatory System: Blood contained within vessels circulating unidirectionally.

• Open Circulatory System: Hemolymph pumped through vessels into body cavities, returning via ostia.

Types of Blood Vessels

• Arteries:

  • Carry oxygenated blood from the heart; largest is the aorta.

• Veins:

  • Return deoxygenated blood to the heart; largest is vena cava.

• Capillaries:

  • Smallest vessels where gas and nutrient exchange occurs.

Mammalian Circulatory System

• Heart pumps blood through three divisions: coronary, pulmonary, and systemic.

Components of Blood

1. Hemoglobin: Distributes oxygen and carbon dioxide.

2. Plasma: Liquid portion containing water, proteins, salts, lipids, and glucose.

3. Cells:

   • Red blood cells: Carry gases.

   • White blood cells: Immune response.

   • Platelets: Blood clotting.

Plant Transport

• Xylem: Transports water from roots to other plants, unidirectionally.

• Phloem: Transports sugars bidirectionally throughout the plant.

Fluid Regulation

Animal Fluid Regulation

• Excretory System: Maintains fluid homeostasis; regulates water and mineral balance.

• Marine Vertebrates: High solute concentrations in blood to match seawater; must reabsorb water.

• Freshwater Vertebrates: Body hypertonic to environment; eliminate excess water.

• Terrestrial Animals: Excretory system filters fluids and eliminates wastes.

Functions of the Excretory System

• Elimination of metabolic wastes (e.g., CO2, H2O, nitrogen).

• Kidneys: Major organ for filtering blood.

• Nephrons: Unit of kidney filtering.

Plant Fluid Regulation

• Photosynthesis: Water utilized in photolysis.

• Osmosis: Water moves from soil to plant due to solute concentrations.

• Transpiration: Water exits leaves via stomata.

Nervous Control

Human Nervous System

• Functions: Sensory input, integration, homeostasis, mental activity, muscle and gland control.

Major Parts of the Brain

1. Brainstem: Connects spinal cord to the brain.

2. Cerebellum: Coordinates motor skills and balance.

3. Diencephalon: Between brainstem and cerebrum.

Lobes of the Brain

• Frontal Lobe: Motor control, problem-solving, speech.

• Parietal Lobe: Touch and pressure, body awareness.

• Temporal Lobe: Smell, hearing, facial recognition.

• Occipital Lobe: Vision.

Plant Nervous Control

• Plants lack nervous systems but have organs that act similarly.

• Apices connect to vascular strands, functioning like nerves.

Plant Sensory Mechanisms

• Tropism Types:

  1. Phototropism: Response to light.

  2. Geotropism: Response to gravity.

  3. Hydrotropism: Response to water.

  4. Thigmotropism: Response to touch.

Chemical Regulation

Animal Chemical Control

• Hormones: Serve as messengers regulating various life processes like growth and homeostasis.

Endocrine Glands in Animals

1. Pituitary Gland

2. Thyroid and Parathyroid Glands

3. Adrenal Glands

4. Pancreas

5. Pineal Gland

6. Thymus Gland

Plant Chemical Control

• Hormones play vital roles in physiological processes.

Immune Control

Animal Immune Systems

• Functions: Filters pathogens, produces white blood cells, generates antibodies, maintains homeostasis.

Immune Responses Types

1. Innate Immunity: Non-specific response existing prior to infection.

2. Acquired Immunity: Specific response to foreign substances, develops based on exposure.

Plant Immune System

• No structural immune system; plant cells have receptors sensing pathogens, triggering defensive mechanisms:

  • Cell wall thickening.

  • Production of antimicrobial compounds.

  • Initiation of apoptosis upon invasion.

Digestive System

Animal Digestive System

• Functions: Ingest food, break it down, absorb nutrients, eliminate waste.

Digestive Process

1. Mechanical Digestion: Initial breakdown via teeth and muscular movement.

2. Chemical Digestion: Enzymatic breakdown into simpler molecules (e.g., carbohydrates into glucose).

Digestive Tract Structure

• Alimentary Canal: Mouth, esophagus, stomach, and intestines.

• Accessory Organs: Salivary glands, pancreas, liver, gallbladder aid digestion.

Animals Without Digestive Systems

• Sponges: Absorb water and trap food particles through specialized cells.

Animals With Digestive Systems

• Coordinated processes for nutrient intake, breakdown, absorption, and waste elimination.