2. 2 Sylvia S. Mader Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Immagini e concetti della biologia

3. 3 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 C1 - Organization and Homeostasis

4. 4 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Four levels of biological organization

5. 5 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Epithelial tissue SECRETION SELECTIVE ABSORPTION PROTECTION Functions of the epithelium

6. 6 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Epithelial cells are connected to each other by tight junctions, adhesion junctions and gap junctions. Epithelium lies on a basement membrane, which acts as a scaffolding and anchors the epithelial tissue to the underlying connective tissue. Epithelial tissue

7. 7 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Cells of the epithelium

8. 8 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Cells of the epithelium

9. 9 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Cells of the epithelium

10. 10 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Cells of the epithelium

11. 11 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Connective tissue connects, protects and supports other tissues. The most abundant tissue in vertebrates- Connective cells are separated by a collagen-rich fluid called matrix which varies from solid (in bones) to semifluid (in cartilage) to fluid (in blood). Connective tissue

12. 12 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Types of Connective Tissue

13. 13 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Types of Connective Tissue

14. 14 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Blood is different from the other connective tissues Blood and has different functions as: Transport of oxygen Transport of nutrients Body heat regulation pH regulation Protection Plasma RBC WBC Platelets

15. 15 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Muscular tissue Muscular cells contains contractile filaments, actin and myosin, that move past each other and change the size of the cell. Major functions: Locomotion of the organism; Movement of internal organs.

16. 16 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Muscular tissue

17. 17 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Nervous tissue Major functions: Sensory input Sensory output Communication within organs Control of muscles and glands Homeostasis

18. 18 axon dendrite cell body Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Neurons transmit impulses Neuron cells are composed of: A cell body (contain nucleus) Dendrites (for input signals) An axon (for output signals)

19. 19 microglia oligodendrocyte astrocyte Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Neuroglia cells Neuroglia cells assist propagation of the impulse and provide nutrients to the neuron. Neuroglia cells include microglia (destroy bacteria and remove dead cells), astrocytes (supply nutrients) and oligodendrocytes (insulate neurons).

20. 20 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Organs and organ systems Organs combine several tissues that function together and cooperate in organ systems. An organ has a precise structure and performs a specific function. Organs exist in all higher biological organisms.

21. 21 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 The skin covers and protects In humans the skin is divided into two strata: the epidermis (stratified epithelium) and the dermis (dense fibrous connective tissue. A subcutaneous layer, the hypodermis (connective tissue) connects the dermis with underlying structures.

22. 22 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Organs Transplant Organs for transplant may come from various sources: Xenotransplantation is the use of animal organs; Tissue engineering allows creation of organs in laboratory.

23. 23 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Organ systems work in homeostasis Several organs of a system work together to carry out a complex function as: Control Sensory input and motor output Transport Maintenance Reproduction

24. 24 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Control Nervous system coordinates the body actions and transmits signals between different locations. Endocrine system regulate the hormones secretion.

25. 25 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Sensory input and motor output Integumentary system is the attachment site for sensory receptors and provides environmental information. Skeletal and muscular systems are responsible for locomotion in response to nervous system instructions.

26. 26 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Transport Cardiovascular system transports nutrients, gases, hormones and other substances through the body. Lymphatic system is a network of conduits carrying the lymph which returns protein and lipids in excess to the circulation.

27. 27 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Maintenance Digestive, Respiratory and Urinary systems are responsible for maintaining the body efficient and constant through the transformation of nutrients or gases and purifying the organism.

28. 28 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Reproduction Organs of the reproductive system include the genitalia (penis and vulva) and a number of internal organs as the gamete producing gonads (testicles and ovaries).

29. 29 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Homeostasis Homeostasis is the maintenance of stable, constant conditions of the body’s internal environment which consists of blood and interstitial fluid (tissue fluid). EQUILIBRIUM

30. 30 Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Homeostasis All organ systems contribute to maintain within normal limits the internal conditions as body temperature, water content, pH, Glucose and CO 2 concentrations.

31. 31 effect Control center Sensor Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012 Negative feedback The negative feedback mechanisms is the principal mechanism in homeostasis and is composed of a sensor and a reaction center (i.e. blood glucose levels).