Homeostasis & Unifying Concepts of Biology Unit f Homeostasis & Unifying Concepts of Biology
Unit f Standards I can describe the structural hierarchy of the body: cell, tissue, organ, organ system and organism I can describe the structure and function of the 4 types of tissues: epithelial, connective, muscle and nervous I can state the structures (organs) of the 12 organ systems I can describe the function of the 12 organ systems I can explain how and why animals regulate their bodies via homeostasis I can provide examples of negative feedback loops at work in the human body and explain why they function to maintain homeostasis
Climbing the Walls Spiderman is a familiar character known for his ability to climb walls Geckos, small lizards commonly found in the tropics can walk up a wall and across ceilings, but how do they do this?
The explanation relates to hairs called setae, on the gecko’s toes containing many split ends called spatulae The ability to “stick” to surfaces results from attractions between molecules on the spatulae and the surface on which the gecko is crawling Rows of setae on a gecko’s foot Spatulae coming from a single seta
A little Hank Intro to Anatomy and Physiology Tissues Part 1: Intro, Nervous and Muscle Tissues Part 2: Epithelial Tissues Part 3: Connective Tissues Part 4: Types of Connective
THE HIERARCHY OF STRUCTURAL ORGANIZATION IN AN ANIMAL THE HIERARCHY OF STRUCTURAL ORGANIZATION IN AN ANIMAL Correlation between structure and function is one of biology’s most fundamental concepts Structure fits function in the animal body Anatomy is the study of structure Physiology studies how structures function
The functions of specific structures result from their specific structures Palm Finger 2 Finger 3 Shaft Barb Barbule Hook Feather structure Wrist Forearm Finger 1 Internal bone structure Figure 20.1
Animal structure has a hierarchy Animal structure has a hierarchy Structure in the living world is organized in a series of hierarchical levels Muscle cell A Cellular level B Tissue level Muscle tissue C Organ level Heart E Organism level Many organ systems functioning together D Organ system level Circulatory system
Epithelial tissue covers the body and lines its organs and cavities Tissues are groups of many similar cells with a common structure and that perform a specific function Epithelial tissue covers the body and lines its organs and cavities Epithelial tissue occurs as sheets of closely packed cells that cover surfaces and line the cavities and tubes of internal organs
Epithelial tissue functions in protection, secretion, and exchange Free surface of epithelium Basement membrane (extracellular matrix) Underlying tissue Cell nuclei A Simple squamous epithelium (lining the air sacs of the lung) D Stratified squamous epithelium (lining the esophagus) B Simple cuboidal epithelium (forming a tube in the kidney) Layers of dead cells Rapidly dividing epithelial cells Colorized SEM E Stratified squamous epithelium (human skin) C Simple columnar epithelium (lining the intestine)
Connective tissue binds and supports other tissues The various types of connective tissue are characterized by sparse cells in an extracellular gel matrix Cartilage- forming cells Matrix D Cartilage (at the end of a bone) Central canal Bone- forming cells E Bone F Blood A Loose connective tissue (under the skin) Elastic fibers Collagen fiber Cell Collagen fibers Cell nucleus B Fibrous connective tissue (forming a tendon) White blood cells Red blood cell Plasma C Adipose tissue Fat droplets
Muscle tissue functions in movement Skeletal muscle is responsible for voluntary body movements Cardiac muscle pumps blood Smooth muscle moves the walls of internal organs such as the stomach Muscle fiber Unit of muscle contraction Junction between two cells Muscle fiber Nucleus Nucleus Muscle fiber Nucleus B Cardiac muscle A Skeletal muscle C Smooth muscle
Nervous tissue forms a communication network The branching neurons of nervous tissue transmit nerve signals that help control body activities Cell body Nucleus Cell extensions LM 330
CONNECTION Artificial tissues have medical uses Artificial tissues can assist in the healing of several injuries
Small intestine (cut open) Several tissues are organized to form an organ Each organ is made of several tissues that collectively perform specific functions Small intestine (cut open) Lumen Epithelial tissue (columnar epithelium) Connective tissue Smooth muscle tissue (2 layers) Epithelial tissue
Organ systems work together to perform life functions Each organ system has one or more functions The digestive and respiratory systems gather food and oxygen A Digestive system Mouth Esophagus Liver Stomach Small intestine Large intestine Anus B Respiratory system Nasal cavity Larynx Trachea Bronchus Lung Bozeman: Organ Systems
The immune system protects the body from infection and cancer The circulatory system, aided by the lymphatic system, transports the food and oxygen The immune system protects the body from infection and cancer C Circulatory system Heart Blood vessels E Lymphatic system D Immune system Bone marrow Thymus Spleen Lymph nodes Lymph vessels
The excretory system disposes of certain wastes The endocrine and nervous systems control body functions F Excretory system Kidney Ureter Urinary bladder Urethra Pituitary gland Thymus Thyroid gland Testis (male) Adrenal gland Pancreas G Endocrine system Ovary (female)
The integumentary system covers and protects the body Skeletal and muscular systems support and move the body I Integumentary system Hair Skin Nails K Muscular system Skeletal muscles Cartilage Bones J Skeletal system
The reproductive system perpetuates the species Female Vas deferens Penis Urethra Testis Prostate gland Male Oviduct Ovary Uterus Vagina L Reproductive systems
Nervous system controls body movement, functioning via communication through nerves
CONNECTION New imaging technology reveals the inner body New technologies enable us to see body organs without surgery
X-rays X-rays can be used for imaging bones and teeth
CT Computed tomography (CT) scans are excellent diagnostic tools
MRI Magnetic resonance imaging (MRI) allows visualization of soft tissues
MRM Magnetic resonance microscopy (MRM) provides three-dimensional images of very small structures
PET Positron-emission tomography (PET) yields information about metabolic processes at specific locations in the body HEARING WORDS SEEING WORDS SPEAKING WORDS GENERATING WORDS MIN MAX
EXCHANGES WITH THE EXTERNAL ENVIRONMENT Structural adaptations enhance exchange between animals and their environment Small animals with simple body construction have enough surface area to meet their cells’ needs Diffusion Two cell layers Mouth Gastrovascular cavity
Larger, complex animals have specialized structures that increase surface area Exchange of materials between blood and body cells takes place through the interstitial fluid Respiratory system Excretory system Digestive system Circulatory system External environment Food Mouth Animal Body cells Interstitial fluid Anus Unabsorbed matter (feces) Metabolic waste products (urine) Intestine Nutrients CO2 O2
The respiratory system has an enormous internal surface area
Homeostatic mechanisms Animals regulate their internal environment in response to changes in external conditions Animals regulate their internal environment to achieve homeostasis, an internal steady state Homeostatic mechanisms External environment Internal environment Small fluctuations Large fluctuations Bozeman: Homeostasis
Homeostasis depends on negative feedback Negative feedback mechanisms keep internal variables fairly constant, with small fluctuations around set points Homeostasis: Internal body temperature of approximately 36–38C Temperature rises above normal Temperature falls below normal Temperature decreases Temperature increases Thermostat shuts off warming mechanisms Blood vessels in skin constrict, minimizing heat loss Thermostat in brain activates warming mechanisms Skeletal muscles rapidly contract, causing shivering, which generates heat Thermostat in brain activates cooling mechanisms Sweat glands secrete sweat that evaporates, cooling body Blood vessels in skin dilate and heat escapes Thermostat shuts off cooling mechanisms
Your Turn!! To help understand the connection between the body systems and homeostasis go to this website: https://ats.doit.wisc.edu/biology/ap/ho/ho.htm and proceed through the 3 topics in order 1. Ben’s Bad Day 2. Ben’s Homeostasis: The Inside Story 3. Does Ben Have Diabetes?
