Transcript Biology 105
Biology 105 Chapter 39: Introduction to structure and function Pages 821-840 Student Outcomes • Compare the structure and function of the 4 main kinds of animal tissues. • Define homeostasis and negative and positive feedback mechanisms Describe the advantages/disadvantages of ectothermy and endothermy Cellular organization • Cells-tissues-organs-organ systemsorganism • An organisms ability to maintain ‘balance’ a constant internal environment is Homeostasis 4 types of animal tissues Based on structure, origin and function Epithelial Connective Muscle Nervous Epithelial Tissue Forms the outer layer of skin and linings of the digestive, respiratory, excretory and reproductive tracts. Everything entering or leaving the body must cross epithelial tissue. Epithelial Tissue Functions • • • • Protection - (epidermis) Absorption - digestive tract Secretion - sweat and hormone glands Sensation - taste buds Connective Tissue • Several types: – Loose - thin filling between body parts, most common – Dense - in dermis, strong (collagen fibers) Tendons/ligaments – Elastic - lungs and walls of arteries – Reticular - framework for liver, spleen and lymph nodes Connective Tissue cont. – Adipose - store and release fat, subcutaneous layer – Cartilage - firm, elastic connections of bone, no nerve or blood supply – Bone - main skeletal tissue - gives support and strength – Blood and lymph - circulating tissues Muscle Tissue Provide movement, muscle cell is known as a muscle fiber-with two proteins (myosin and actin) 3 types: 1. Skeletal - ‘voluntary’ large muscles attached to bones 2. Cardiac - ‘Involuntary’ 3. Smooth - Internal organs of the digestive system. Also ‘Involuntary’ Nervous Tissue • Neurons and glial cells – Receive signals and transmits these to the brain or from the brain. Neoplasm (tumor) • Abnormal grow of tissue – Two types: benign and malignant • Benign – distinct shape, easy to remove • Malignant – no communication with surrounding cells, grow and divide in an uncontrolled way. (Cancer) Cancer • Sarcomas – cancer of connective/muscle tissue • Carcinomas – cancer of epithelial tissue (breast, prostate, ovarian) • Most tumors will have a dormant stage – than will send signal to promote blood vessel growth=rapid tumor growth Body Systems • Body is divided into major systems. • Each system has specific functions, but rely on each other to perform functions to maintain homeostasis. Body Systems • • • • • • • • • • Integumentary Skeletal Muscular Nervous Endocrine Circulatory Lymphatic Respiratory Digestive Urinary Feedback systems • Known as biofeedback systems • Maintain homeostasis – Negative feedback mechanism – Positive feedback mechanism Negative feedback mechanisms • Most common of body feedback systems • Reverse the current course to bring the body back into homeostasis (set point) – Controlling temperature Positive feedback mechanisms • These intensify the changes – Swallowing, birth process, reflexes – Positive feedback mechanisms may continue the body’s path away from homeostasis. Thermoregulation • Type types – Ectotherm - heat source comes from an outdoor source (sun, warm rock, etc) – Endotherm - heat source is internal Ectotherm • Advantages – Little energy used for warmth – Can survive on less food and in cooler climates (water) – Can devote more energy to reproduction and growth Ectotherm • Disadvantages – Activity limited during certain times of the day – Cannot escape predators during cool times. – Cannot hunt during cool times. – Overheating can be an issue. Endotherm • Advantages – Constant body temperature - leads to more enzymatic activity – Can be active in cold temps. Endotherm • Disadvantages – Body cannot tolerate significant changes – Large amounts of energy required to keep steady body temp. (especially during down times like sleeping) Endotherm adaptations • To survive, endotherms have the following adaptations: – Blubber, feathers, and hair and other adaptations reduce heat loss. – Torpor - decrease in body temp and metabolic activity • Hibernation and Estivation are prolonged periods • of Torpor. Acclimatization – adapting to seasonal changes.