Umm Al-Qura University بسم الله الرحمن الرحيم Umm Al-Qura University Health Sciences College at Al-Leith Department of Public Health Lecture (3)

biology of Insects and structure 2- Internal Anatomy

Objectives 1/ Recognize of Internal Morphology and biology of arthropods. 2/ Define types of arthropods Metamorphosis .

1- The Respiratory System Function: Intake of oxygen removal of CO2 Spiracles: external openings (2 pair on Thorax, 8 pair on Abdomen) Trachea/tracheoles: air tubes Air sacs: air storage

Respiratory System

Respiratory System

2- The Circulatory System An open system (unlike vertebrates) The only blood vessels are the heart and dorsal aorta Hemocoele – open blood cavity of insect

The Circulatory System Principle functions: transport food, waste products, and hormones from one part of the body to another. other functions: lubrication of internal structures act as a hydraulic medium protect the body form infection serve as a simple storehouse for metabolic waste products

Circulatory system Aorta portion of

3- Nervous System

Features of nervous system: Brain in head, and a ganglia in each section Ganglia may coordinate the impulses of specific regions

4- Digestive & Excretory Systems

Features of digestive tract: A tube divided into 3 sections (foregut, midgut, & hindgut) Many insects are efficient at removing water from food (results in dry fecal pellets, also called frass). Waste is primarily uric acid.

5- Reproductive System

Abdomen – digestion, respiration and reproduction reproductive & oviposition structures spiracle Abdomen has 7-11 segments Each segment has a pair of spiracles

Insects will complete one of two different life cycles: 1- Incomplete Metamorphosis - gradual change. 2- Complete Metamorphosis - complete change.

Incomplete Metamorphosis: Egg. Early nymph (no wings). Late nymph (wings developing). Adult.

Complete Metamorphosis: Egg. Larva. Pupa. Adult.

What are the basic characteristics of insects? Are invertebrates. Have an exoskeleton. Segmented; Bilateral. Breathe through holes called spiracles. Have 6 legs (3 pairs of legs). Have compound eyes. Open circulatory system. Ventral nervous system. Don’t live very long lives.

2. Reproductive capacity & adaptibility WHY ARE INSECTS SO SUCCESSFUL? 1. Ability to fly 2. Reproductive capacity & adaptibility 3. Resist drying - exoskeleton 4. Small size 5. Metamorphosis

Thanks Radia 28