STRUCTURE AND FUNCTION IN ANIMAL TISSUES

Transcription

1 Chapter 20 UNIFYING CONCEPTS OF ANIMAL STRUCTURE AND FUNCTION Chapter 20: Big Ideas Structure and Function in Animal Tissues Organs and Organ Systems External Exchange and Internal Regulation STRUCTURE AND FUNCTION IN ANIMAL TISSUES Structure fits function at all levels of organization in the animal body! Anatomy is the study of structure.! Physiology is the study of function.! Animal structure hierarchy: Cells have own metabolism, communicate with other cells Tissues are an integrated group of similar cells Organs consist of two or more tissues Organ s consist of multiple organs Organisms are made of many organ s working together Figure 20.1 Cellular level Muscle cell Tissue level Muscle tissue EVOLUTION CONNECTION: An animal s form reflects natural selection! The body plan of an organism Reflects relationship between form & function results from natural selection does not imply a process of conscious invention Organ level Heart Organ level Circulatory Organism level Many organ s functioning together Streamlined / tapered bodies increase swimming speeds

2 Tissues are groups of cells with a common structure and function! Animals have four main categories of tissues: 1. epithelial tissue, 2. connective tissue, 3. tissue, and 4. nervous tissue. Epithelial tissue! Epithelial tissues: sheets of closely packed cells cover body surfaces line internal organs and cavities Outer portion of our skin and intestines = one big tube! Connective tissue Figure 20.5! Connective tissue binds and supports other tissues Cells scattered through an extracellular matrix Cells produce and secrete the matrix, which is a web of s in a liquid, jelly, or solid 6 types of connective tissue Cell nucleus Collagen Elastic s Loose connective tissue (under the skin) Cell nucleus Collagen s Fat droplets Fibrous connective tissue (forming a tendon) Blood Adipose tissue White blood cells Red blood cell Plasma Bone Cartilage (at the end of a bone) Central canal Matrix Boneforming cells Cartilageforming cells Matrix Connective tissue Connective tissue 1. Loose connective tissue Holds tissues and organs in place e.g. under skin to join skin to underlying tissues 2. Fibrous connective tissue densely packed bundles of collagen s e.g. tendons attach to bone e.g. ligaments join bones together 3. Adipose tissue stores fat, pads & insulates body, stores energy 4. Cartilage strong and flexible skeletal material commonly surrounds the ends of bones, + nose, ears, vertebral discs. 5. Bone Rigid matrix of collagen s (but still flexible in living body!) embedded in a hard mineral substance containing calcium, magnesium, and phosphate. 6. Blood Fluid connective tissue Blood matrix = plasma (water, salts, proteins) Transport and immunity function

3 Figure 20.6 Muscle tissue functions in movement Muscle! Three types of vertebrate tissue: Muscle (cell) Unit of contraction Junction between two cells Nucleus 1. Skeletal causes voluntary movements. Nuclei 2. Cardiac pumps blood. 3. Smooth moves walls of internal organs, such as the intestines, bladder, arteries. Mostly involuntary Cardiac Muscle Nucleus Skeletal Smooth Nervous tissue forms a communication network ORGANS AND ORGAN SYSTEMS! Nervous tissue senses stimuli transmits & processes information directs responses! Neurons carry signals by conducting electrical impulses. Organs are made up of several tissues Organs are made up of several tissues! Each tissue performs specific functions in the organ.! Another example: Small Intestine Lined with epithelium! The heart has extensive that generates contractions, epithelial tissues that line the heart chambers, connective tissues that make the heart elastic, and includes connective tissues that contain blood vessels, and has two layers of smooth that help propel food. neurons that regulate contractions. Inner surface: many fingerlike projections increase surface area for absorption.

4 Organ s work together to perform life s functions 12 Major Organ Systems! The skeletal and muscular s support, protect, and move the body.! Group of several organs working together to perform one or more vital body functions! The respiratory obtains oxygen, disposes of carbon dioxide. 12 Major Organ Systems in Vertebrates! The digestive / excretory obtains, processes, and assimilates nutrients, disposes of solid wastes.! The circulatory transports the materials obtained by respiratory and digestive s.! The urinary disposes of liquid wastes. Figure 20.10_L 12 Major Organ Systems (cont.) Circulatory Respiratory Nasal cavity Hair Skin Trachea Heart! The integumentary covers the body. Integumentary Pharynx Larynx Bronchus Nails Lung! The lymphatic and immune s protect the body from infection. Blood vessels Skeletal Bone! The nervous and endocrine s control and coordinate body functions.! The reproductive produces offspring. Cartilage Urinary Muscular Digestive Mouth Esophagus Skeletal s Liver Kidney Ureter Urinary bladder Urethra Stomach Small intestine Large intestine Anus Figure 20.10_R Endocrine Hypothalamus Pituitary gland Thymus Thyroid gland Adrenal gland Parathyroid gland Imaging technology reveals the inner body Lymphatic and immune s Thymus Lymph nodes Spleen Appendix Bone marrow Pancreas Testis (male) Lymphatic vessels Ovary (female) Reproductive Nervous Spinal cord Nerves Female Oviduct Seminal vesicles Male Prostate gland Vas deferens Ovary Uterus Drawbacks include cancer risk (high E radiation), not useful for soft tissues, 2-dimensional! Magnetic resonance imaging (MRI) Sense organ (ear)! X-rays (c1895) create images of hard structures such as bones and teeth. Aligns H atoms in cellular water & then knocks out of alignment this sends pulse picked up by scanner provides three-dimensional images of very small structures, including soft tissue Penis Vagina Testis Urethra

5 Imaging technology reveals the inner body! Computed Tomography (CT) Scan high-resolution images of cross sections of the body, puts them together for full image can detect small differences between normal and abnormal tissues in many organs, esp. abdomen & brain! Positron-emission tomography (PET) helps identify metabolic processes. 1 st inject patient with radioactively-labeled glucose Metabolically-active cells take up more glucose CT and PET images can be combined for an even more informative image. Tumors Animals regulate their internal environment INTERNAL REGULATION! Homeostasis = active maintenance of a steady state within the body. External conditions may fluctuate wildly. Homeostatic mechanisms regulate internal conditions. Homeostasis Ptarmigan maintains internal temperature through metabolism and insulation. Homeostasis depends on negative feedback! Control s detect change and direct responses.! Negative-feedback mechanisms keep internal variables steady and permit only small fluctuations around set points. Gecko maintains internal temp. through behavior modification (sun basking). Example: home thermostat

6 Figure 20.15_s2 activates cooling Figure 20.15_s3 Sweat evaporates, cooling the body. activates cooling Blood vessels dilate. Temperature rises above set point Temperature rises above set point Homeostasis: Body temperature approximately 37 C Homeostasis: Body temperature approximately 37 C Temperature falls below set point Temperature falls below set point Blood vessels constrict. activates warming Shivering generates heat. activates warming Figure 20.15_s4 Sweat evaporates, cooling the body. activates cooling Temperature decreases Cooling mechanisms shut off. Blood vessels dilate. Temperature rises above set point Homeostasis: Body temperature approximately 37 C Temperature increases Warming mechanisms shut off. Temperature falls below set point Blood vessels constrict. Shivering generates heat. activates warming