1 Organization and Homeostasis

2 Levels of biological organization Chemical Cellular Tissue Organs System Level Organismic Level

3 Levels of Structural Organization  Chemical Level - atomic and molecular level  Cellular level - smallest living unit of the body  Tissue level Group of cells and the materials surrounding them that work together on one task 4 basic tissue types: epithelium, muscle, connective tissue, and nerve

4 Epithelial tissue SECRETION SELECTIVE ABSORPTION PROTECTION Functions of the epithelium

5 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

6 Cells of the epithelium

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10 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

11 Types of Connective Tissue

12 Types of Connective Tissue

13 Blood is different from the other connective tissues Blood has different functions as: Transport of oxygen Transport of nutrients Body heat regulation pH regulation Protection Plasma RBC WBC Platelets

14 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.

15 Muscular tissue

16 Nervous tissue Major functions: Sensory input Sensory output Communication within organs Control of muscles and glands Homeostasis

17 axon dendrite cell body Neurons transmit impulses Neuron cells are composed of: A cell body (contain nucleus) Dendrites (for input signals) An axon (for output signals)

18 microglia oligodendrocyte astrocyte 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).

19 Read the description of the following tutorial, watch the animation and answer the quiz: Watch the following animation and write the names of the animal tissues, organs and organ systems presented: living-world/level-of-organization-hierarchy.php Watch the following animation about the epithelial tissues: mal-tissue.php Are there some tissues that you do not know? Animations and activities

20 Organs and organ systems  Organ level - consists of two or more types of primary tissues that function together to perform a particular function or functions Example: Stomach Inside of stomach lined with epithelial tissue Wall of stomach contains smooth muscle Nervous tissue in stomach controls muscle contraction and gland secretion Connective tissue binds all the above tissues together  Organ system - collection of related organs with a common function, sometimes an organ is part of more than one system  Organismic level - one living individual.

21  Groups of organs that perform related functions and interact to accomplish a common activity essential to survival of the whole body.  Do not act in isolation from one another.  Human body has 11 organ systems. Organ systems

22 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.

23 Watch the following videos: 1) (about skin) 2) (about skin, with subtitles) 3) (a review of cell, transport and tissues) Read the descriptions on pages 1, 2, and 3, answer the questions on pages 2 and 3, and solve the quiz on page 5 at: coSiteNavigation_allTopic=1 Videos and activities

24 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

25 Control Nervous system coordinates the body actions and transmits signals between different locations. Endocrine system regulates the hormones secretion.

26 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.

27 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.

28 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.

29 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).

30  Defined as maintenance of a relatively stable internal environment  Does not mean that composition, temperature, and other characteristics are absolutely unchanging  Homeostasis is essential for survival and function of all cells  Each cell contributes to maintenance of a relatively stable internal environment Homeostasis

31 Homeostasis Homeostasis is the maintenance of stable, constant conditions of the body’s internal environment which consists of blood and intestitial fluid (tissue fluid). Homeostasis involves dynamic mechanisms that detect and respond to deviations in physiological variables from their “set point” values by initiating effector responses that restore the variables to the optimal physiological range. EQUILIBRIUM

32 Homeostasis All organ systems contribute to maintain within normal limits the internal conditions as body temperature, water content, pH, Glucose and CO 2 concentrations.

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34 Homeostatic Control Systems  In order to maintain homeostasis, control system must be able to  Detect deviations from normal in the internal environment that need to be held within narrow limits  Integrate this information with other relevant information  Make appropriate adjustments in order to restore factor to its desired value

35 effect Control center Sensor 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).

36 Read the description on pages 4, 5, 6, and 7, see the animation on page 4 and answer the questions on pages 5, 6, and 7 of the document at: ugar/.cfm?coSiteNavigation_allTopic=1 Read the description on pages 1 and 2 of the document at: a/homeostasis/removal_waste_water_control/revision/1/ Read the description, watch the video and the animation that can be found at: _aqa/homeostasis/temperature_control/revision/1/ Animations and activities