B120 - W24 - Stud - T11 - Animal Form and Function.pdf

Animal Form and Function Form and Function Wolf Sheep Different shapes of feathers Why these forms, shapes and size? Different groups with similar shapes Different shapes of beak Form and Function Animal form and function are correlated at all levels of biological organization. Size and shape affect...

Animal Form and Function Form and Function Wolf Sheep Different shapes of feathers Why these forms, shapes and size? Different groups with similar shapes Different shapes of beak Form and Function Animal form and function are correlated at all levels of biological organization. Size and shape affect the way an animal interacts with its environment. Many different animal body plans have evolved and are determined by the genome. Different shapes of feathers Different shapes of beak By Onkar Bains, with modifications by Vinicius Cavicchioli Azevedo Form and Function Size and shape of single-cell organisms and tissues of multi-cellular organisms are associated with their capacity to exchange substances with the surrounding environment. o Animals rely on exchange with the environment to acquire nutrients and gases necessary for metabolic function and eliminate wastes. o Exchange occurs as substances dissolved in the aqueous medium diffuse and are transported across the plasma membrane Form and Function o Aquatic single-celled organisms developed folds in the plasma membrane that increase its surface area, increasing the exchange (diffusion) rate of molecules between the environment and the entire volume of the cytoplasm. Lower Surface Area Higher Surface Area Lower diffusion rate Higher diffusion rate Exchange Form and Function - Rate of Diffusion Fick’s Law Rate of diffusion = Diffusion constant (dependent of solubility and temperature) K x A x (C2 – C1) D Surface area Difference in concentration on either side of the membrane Distance (Thickness of the diffusion barrier) Multicellular organisms with a sac body plan have body walls that are only two cell layers thick, facilitating diffusion of materials. In flat animals such as flatworms and tapeworms, the distance between cells and the environment is minimized. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings More complex organisms have highly folded internal surfaces to increase surface area for exchanging materials Internal exchange surfaces of complex animals Why are cells so small? The rate of material exchange in and out of cell is a function of its surface area Small cells have a high surface area to volume ratio, which allows more stuff to move in and out of the cell As cell grows, volume increases faster than surface area (leading to a decreased surface area-to-volume ratio) Cell division restores a viable surface area-to-volume ratio (surface area / volume) Therefore, in order to build larger organisms, they must be built up from smaller cells By Onkar Bains, with modifications by Vinicius Cavicchioli Azevedo 1. The mammalian small intestine's main function is to absorb nutrients from digested food; nutrients diffuse from the lumen of the intestine to the bloodstream. Anatomically, the mammalian small intestine has small folds called microvilli that increase its surface area. Why is increasing the small intestine surface area important for mammals? Make predictions about the absorption of nutrients in the absence of microvilli. 2. How does diffusion limit the size of an organism? How is this counteracted? 1. Mammalian small intestine main function is to absorb nutrients from digested food, nutrients diffuse from the lumen of the intestine to the blood stream. Anatomically, mammalian small intestine has small folds called microvilli's that increase its surface area. Why increasing small intestine surface area is important for mammals? Make predictions about the absorption of nutrients in the absence of microvilli According to Fick’s law, the diffusion rate is directly correlated to the surface area. Therefore, the increase in the surface area leads to a higher diffusion rate, allowing for higher absorption of nutrients. So, a mammal that lacks microvilli on its small intestine will absorb fewer nutrients and take more time to absorb the nutrients. 2. How does diffusion limit the size of an organism? How is this counteracted? Diffusion is effective over a very short distance. If a cell exceeds this distance in its size, the center of the cell cannot get adequate nutrients, nor can it expel enough waste to survive. To compensate for this, cells can loosely adhere to each other in a liquid medium, or develop into multi-celled organisms that use circulatory and respiratory systems to deliver nutrients and remove wastes. Review: Levels of Biological Organization Organ system = group of organs that work together to perform a certain task Organ = functional grouping of tissues Tissue = collection of cells that is specialized to perform one or more particular function Cell = lowest level of organization that can perform all activities required for life Organelle = a differentiated structure within a cell that performs a specific function Molecule = smallest particle in a chemical element or compound that has the chemical properties of that element or compound By Onkar Bains, with modifications by Vinicius Cavicchioli Azevedo By Onkar Bains, with modifications by Vinicius Cavicchioli Azevedo Histology Branch of biology that studies tissue structure and organization Different tissues have different structures that are suited to their functions Types of Tissues https://cdn1.byjus.com/wp-content/uploads/2019/08/Types-of-tissues.png Interstitial Fluid The fluid that fills the spaces between cells The body fluid between blood vessels and cells https://steemit.com/science/@kastiuz/interstitial-fluid-cycle-and-its-relationship-with-cancer https://i.pinimg.com/736x/f2/75/b5/f275b58c1724245cac9b36f337c1998a.jpg Epithelial tissue - covering & lining Epithelial tissue consists of tightly packed cells that cover the outside of the body and line the organs and cavities within the body o It contains cells that are closely joined together by tight junctions. The shape of epithelial cells may be cuboidal (like dice), columnar (like bricks on end), or squamous (like floor tiles) https://slideplayer.com/15454292/93/images/slide_7.jpg Copyright © 2008 Azevedo Pearson By Onkar Bains, with modifications by Vinicius Cavicchioli Education, Inc., publishing as Pearson Benjamin Cummings Simple epithelium: ü Single layer of cells Stratified epithelium ü Multiple layers of cells Pseudostratified epithelium ü Single layer of cells but looks like multiple layers http://www.knowswhy.com/wpcontent/uploads/2017/09/Difference-betweensimple-and-stratified-epithelium.jpg In some pseudo-stratified epithelia, the cells become so crowded that the nuclei become displaced and form several rows in the epithelium (this makes the epithelium appear to be stratified) By Onkar Bains Connective tissue Connective tissue mainly binds and supports other tissues. o It contains cells that are loosely arranged in a liquid, jellylike or solid matrix In vertebrates, there are five major types of connective tissue 1. Loose connective tissue - Adipose tissue 2. Fibrous connective tissue 3. Bone 4. Cartilage 5. Blood Copyright © 2008 Azevedo Pearson By Onkar Bains, with modifications by Vinicius Cavicchioli Education, Inc., publishing as Pearson Benjamin Cummings Loose Connective Tissue Loose connective tissue binds epithelia to underlying tissues and holds organs in place Adipose tissue is a type of loose connective tissue that stores fat for insulation and fuel (each adipose cell contains a large fat droplet that swells when fat is stored and shrinks when the body uses fat as fuel) Copyright © 2008 Azevedo Pearson By Onkar Bains, with modifications by Vinicius Cavicchioli Education, Inc., publishing as Pearson Benjamin Cummings Fibrous Connective Tissue Fibrous (or dense) connective tissue is found in tendons, which attach muscles to bones, and ligaments, which connect bones at joints Copyright © 2008 Azevedo Pearson Education, Inc., publishing as Pearson Benjamin Cummings By Onkar Bains, with modifications by Vinicius Cavicchioli https://histology.siu.edu/ssb/NM002b.htm Bones Bone is mineralized and forms the skeleton § Osteoblasts are immature bone cells that deposit a matrix of collagen (as new bone is formed, a few of the active osteoblasts will mature into osteocytes) § Then, calcium and phosphate ions combine with collagen and harden within the matrix into the mineral hydroxyapatite [Ca5(PO4)3(OH)] § The combination of hard minerals and flexible collagen makes bone harder than cartilage without being brittle By Onkar Bains Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Bones § Osteoclasts release an acid to dissolve collagen and mineral coating (in order to raise calcium levels in blood if they are too low) § The microscopic structure of hard mammalian bones consists of repeating units called osteons (each osteon has concentric layers of mineralized matrix deposited around a central canal containing blood vessels and nerves that service the bone) Copyright © 2008 Azevedo Pearson By Onkar Bains, with modifications by Vinicius Cavicchioli Education, Inc., publishing as Pearson Benjamin Cummings Cartilage Cartilage is a strong and flexible support material. § Cartilage has an abundance of collagenous fibres embedded in a rubbery matrix made of a substance called chondroitin sulphate, a proteincarbohydrate complex. Chondroblasts § Chondroblasts produce the chondrocytes and extracellular matrix of the cartilage. matrix § Chondrocytes are embedded in the matrix, maintaining it by secreting collagen and chondroitin sulphate. chondrocytes § The composite of collagenous fibres and chondroitin sulphate makes cartilage a strong yet somewhat flexible support material. Copyright © 2008 Azevedo Pearson By Onkar Bains, with modifications by Vinicius Cavicchioli Collagenous fibers Education, Inc., publishing as Pearson Benjamin Cummings Cartilage In humans, Cartilage is found in the nose, ears, intervertebral discs, articulations and part of the rib cage. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Blood Tissue Blood is composed of blood cells and cell fragments in blood plasma § The matrix is a liquid called plasma, consisting of water, salts, and a variety of dissolved proteins § Suspended in the plasma are erythrocytes (red blood cells), leukocytes (white blood cells) and cell fragments called thrombocytes (platelets) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings By Onkar Bains, with modifications by Vinicius Cavicchioli Azevedo Muscle Tissue Muscle tissue consists of long cells called muscle fibers, which contract in response to nerve signals It is divided in vertebrate body into three types: ü Skeletal muscle is attached to bones and is responsible for voluntary body movement ü Smooth muscle mainly lines internal organs (i.e., digestive tract, urinary tract, reproductive tract, blood vessels, etc.) and is responsible for involuntary body activities ü Cardiac muscle is responsible for heart contraction to help pump blood throughout body (under involuntary control) By Onkar Bains, with modificationsCopyright by Vinicius Cavicchioli Azevedo © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings https://medlineplus.gov/ency/images/ency/fullsize/19917.jpg Muscle Tissue intercalated disks = gap junctions that provide direct electrical coupling between heart cells) By Onkar Bains Intercalated disks = spindle-shaped SMOOTH SKELETAL CARDIAC Striated No Yes Yes Voluntary or involuntary control Involuntary Voluntary Involuntary Multinucleated or mononucleated Mononucleated (1 nucleus per cell) Multinucleated (many nuclei per cell) Mononucleated (1 nucleus per cell) Shape Spindle (fusiform) Long and cylindrical Short and branched Intercalated discs No No Yes Location in body Found lining many of hollow internal structures of the human systems (excretory, reproductive, digestive, circulatory) along with bronchioles of respiratory system Muscles attached to bone/skeletal system…as well as in anal sphincter and wall of pharynx…also this muscle type helps in pushing venous blood in one direction Heart By Onkar Bains Nervous Tissue Nervous tissue senses stimuli and transmits electrical signals throughout the animal Nervous tissue contains: o Neurons, or nerve cells, that transmit nerve impulses o Glial cells, or glia, that help nourish, insulate, and replenish neurons (i.e., provide support and protection for neurons) Neuron Glial cells By Onkar Bains, with modificationsCopyright by Vinicius Cavicchioli Azevedo © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Nervous Tissue Most neurons have two distinct types of projections from the cell body, where the nucleus is located o Short, branching dendrites, which transmit electrical signals from adjacent cells to the neuronal cell body o Long axons, which carry electrical signals from the cell body to other cells By Onkar Bains Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Feedback Loops There are two types of feedback loops: o Negative feedback loops o Positive feedback loops By Onkar Bains, with modificationsCopyright by Vinicius Cavicchioli Azevedo © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Negative Feedback Loops Organisms use homeostasis to maintain a “steady state” or internal balance regardless of changes in the external environment. Organisms commonly use negative feedback loops to homeostatically regulate some variables. o Negative feedback acts to reverse a trend in order to maintain a particular variable within a narrow range o Example of variables that undergo negative feedback in humans = body temperature, blood pressure, blood pH, and blood glucose levels By Onkar Bains, with modificationsCopyright by Vinicius Cavicchioli Azevedo © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Body temperature Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Blood glucose levels Positive feedback loops occur in animals, but do not usually contribute to homeostasis ü Instead, positive feedback escalates a trend! ü For example, during childbirth, the pressure of the baby’s head against sensors near the opening of the uterus stimulates uterine contractions ü These cause greater pressure against the uterine opening, heightening the contractions, which cause still greater pressure ü Positive feedback brings childbirth different sort process from maintaining a steady state By Onkar Bains Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 1. When a person leads a sedentary life his skeletal muscles atrophy, but his smooth muscles do not. Why? 2. How is a condition such as diabetes a good example of the failure of a set point in humans? 3. Why are negative feedback loops used to control body homeostasis? 1. When a person leads a sedentary life his skeletal muscles atrophy, but his smooth muscles do not. Why? Skeletal muscles are involved in voluntary motion, so the person has to make the choice to work those muscles through exercise or movement. Smooth muscles are involved in involuntary activities of the body (ex. blood vessel expansion and contraction, intestinal peristalsis) so they are active even when a person is sedentary. 2. How is a condition such as diabetes a good example of the failure of a set point in humans? Diabetes is often associated with a lack in production of insulin. Without insulin, blood glucose levels go up after a meal, but never go back down to normal levels. 3. Why are negative feedback loops used to control body homeostasis? An adjustment to a change in the internal or external environment requires a change in the direction of the stimulus. A negative feedback loop accomplishes this, while a positive feedback loop would continue the stimulus and result in harm to the animal.