Immagini e concetti della biologia Sylvia S. Mader Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

C1 - Organization and Homeostasis Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Four levels of biological organization Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Epithelial tissue 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. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Functions of the epithelium Epithelial tissue Functions of the epithelium SECRETION PROTECTION SELECTIVE ABSORPTION Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Cells of the epithelium Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Cells of the epithelium Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Cells of the epithelium Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Cells of the epithelium Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Connective tissue 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). Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Types of Connective Tissue Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Types of Connective Tissue Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Blood is different from the other connective tissues Plasma RBC WBC Platelets Blood has different functions as: Transport of oxygen Transport of nutrients Body heat regulation pH regulation Protection Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Muscular tissue Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Nervous tissue Major functions: Sensory input Sensory output Communication within organs Control of muscles and glands Homeostasis Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Neurons transmit impulses axon dendrite cell body Neuron cells are composed of: A cell body (contain nucleus) Dendrites (for input signals) An axon (for output signals) Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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). Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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 Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Control Nervous system coordinates the body actions and transmits signals between different locations. Endocrine system regulates the hormones secretion. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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). Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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 Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

Homeostasis All organ systems contribute to maintain within normal limits the internal conditions as body temperature, water content, pH, glucose and CO2 concentrations. Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018

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). effect Control center Sensor Sylvia S. Mader, Concepts of Biology © Zanichelli editore, 2018