Materials of Animal Forms and Functions in Biology II | BIO 1144, Study notes of Biology

Download Materials of Animal Forms and Functions in Biology II | BIO 1144 and more Study notes Biology in PDF only on Docsity! Test #3 Material (Chapters 40-46) Ch. 40 Animal Form and Organization Levels of Organization:  Cellular- Phylum Porifera (sponges)  Tissue- Phylum Cnidaria, Phylum Ctenophora Aggregation of cells with common function  Organ- aggregation of tissues into a larger unit  Organ system- organs functioning together for a common purpose  Integumentary  Outer covering of body  Skin and all accessory structures  Protection  Digestive  Intake and breakdown of molecules  Digestion absorption  Release of solid waste  Nervous  Brain and spinal cord (central nervous system)  Peripheral nervous system  Muscular/ Skeletal  Involved in locomotion  Internal protection  Movement of materials through body  Circulatory  Transport of materials through body within vessels  Ex. Gases, food, H2O  Respiratory  Gas exchange  Excretory  Urinary  Filters blood of body for waste removal  Kidneys are the major organ  Reproductive  Gamete production  Hormonal regulation  Endocrine  MOST of hormonal regulation  Immune/ Lymphatic  Defense against internal and external attacks  4 Basic Tissue types:  Epithelial  Form sheets  Cover or line surfaces and cavities  Cells tightly packed  Separated from underlying connective tissue by basal lamina- basement membrane  Classification:  Number of cell layers  Simple epithelium (1 layer)  Stratified epithelium (multiple layers)  Morphology- shape and structure of cell  Squamous- mostly flat, centralized nucleus  Cuboidal- block like, centralized nucleus  Columnar- elongate tall cells, nucleus in lower 1/3 of cell  Types of Epithelium Tissue  Simple squamous  Single layer flat cells  Function:  Absorption  Secretion  Exchange of materials  Usually lines duct or cavity  Simple cuboidal  Single layer cube cells  Function:  Absorption  Secretion  Possibly transport  Simple columnar  Single layer tall cells  Function:  Absorption  Secretion  Protection  Pseudostratified columnar  Simple tissue  All cells in contact with basal lamina  Cells vary in height  Still only one layer thick but may look like more  Function:  Absorption  Secretion  Protection  Stratified squamous  Multi-layered  Outermost cells typically dead  Cytoplasm replaced by hardened keratin  Stratified cuboidal  2-3 cells thick  Function:  Transport  Barrier  Stratified columnar  2-3 cells thick  Function:  Transport  Barrier  Transitional  Many layers of cells of different sizes and highly stretchable  Connective  Connect, anchor, support, and bind structures  Types:  Loose (areolar)- cells loosely arranged  Growth  Reproduction The amount of food required increases from survival to reproduction  The gut tract  2 types  Blind gut system  No cavity btwn the gut and the body wall (no mesoderm)  Only one opening which functions as entrance for food and exit of waste  Primitive type of gut system  Tube within a tube arrangement  Advanced form  Flow through digestive tube  There is an entrance and exit (2 openings)  Fluid filled body cavity (coelom) between gut and body wall  Separate openings  Digestive enzymes  Primarily hydolases  Split chemical bonds by adding a water molecule  Grouped into compounds:  Carbohydrases- break down carbs  Proteases- break down proteins  Lipases- break down lipids  Functions of the digestive system  Digestion  The breakdown of large molecules into smaller ones  Can be chemical (water and enzymes) or mechanical  Chemical- releasing enzymes and water  Mechanical- chewing, physical breakdown  Absorption  Taking of digestive molecules into the blood stream  Transport  The movement of digestive food through the gut tract  Elimination  The removal of undigested or unabsorbed molecules  Secretion  Alimentary Canal  Digestive tract or tube  Sometimes called the GI tract  Tube between the mouth and anus that food/waste pass through  Composed of different organs  Regions of the Alimentary Canal  Region of Reception  Buccal cavity- mouth and all accessory structures  Involved in chemical and mechanical digestion  Includes:  Teeth and tongue for mechanical digestion  Salivary glands which secrete enzymes in mouth cavity (secrete amylase)  Pharynx- back of mouth cavity; point where digestive and respiratory systems cross paths  This is why it is easy to choke on food  Region of Conduction  Move food from mouth down  Esophagus- muscular structure; tube from mouth cavity to next region  Peristalsis occurs (not just gravity moving food)  Rhythmic muscular contractions to force a bolus of food down 10 diameter tube  Forcing the molecule of food down that is larger than diameter of tube  Force bolus of food to the next region  Region of Storage and Digestion  Stomach (mostly vertebrates)  Large stretchable sack  Storage mechanism for better digestion of food  Chemical and mechanical digestion (in some animals)  Having stomach as storage keeps animal from having to eat as often  Stomach can store food temporarily  Being broken down more while in the stomach  Inside is lining called ruggae- folds of the inner lining of stomach that allow for expansion  Wall of stomach is lined with smooth muscle on outside of epithelial tissue  3 layers of smooth muscles  First layer runs vertical  Second runs horizontal  Third runs vertical  This pattern causes the cells of the muscle not to line up evenly so contraction occurs in different directions  Lining up of cells in different direction and causes churning in stomach- when it contracts it mixes food with chemicals (Chemical and mechanical digestion)  Enzymes cause chemical digestion  This is where protein digestion begins  The inner lining is epithelium with pits and glands  Mucous cells  Chief cells- secrete pepsinogen (technically and inactive enzyme)  Parietal cells- secrete hydrochloric acid (mainly kills bacteria)  Lumen- cavity of stomach  Pepsinogen and HCl combine to form the enzyme pepsin (enzyme that breaks down proteins)  Minimal amount of absorption in the stomach  Only thing absorbed is lipid soluble material  Like aspirin and alcohol  Crop-  Found in birds and insects  Enlarged lower portion of esophagus (so they have the crop and stomach to store food)  Region of Terminal Digestion and Absorption  Almost all absorption  Small intestine (SI)- (vertebrates) where almost all absorption occurs In insects this area is called the midgut  Cemical digestion of lipids and nucleic acids begin and end in the SI  Chemical digestion of carbs and proteins are continued and completed  Length of small intestine in mammals is estimated to be 8 times their height (tightly coiled)  Requires muscle contraction  3 regions of the small intestine:  Duodenum- beginning section  Where most digestion and absorption occurs  Many secretions into this region  Jejunum  Ileum  These are shorter sections that duodenum; absorption occurs here  In order for absorption to occur, tube must be lined with epithelial tissue Plicae circular  Simple epithelium (1 layer of cells)  Epithelium (surface) has modifications to increase the absorption area  Goal is to provide as much surface area as possible  Plicae circulars- folds in the epithelial tissue that increases the surface area 2-3 times  Villus (villi)- fingerlike projections off the plicae into the cavity; increases the surface area 10 times  Microvilli- folding of plasma membrane of epithelia cells that line the villi; increases the surface area 20 times  This increase in surface area is a major enhancement that greatly increases absorption  Region of H2O Absorption and Concentration of Solids  Large intestine (LI)- vertebrates Hindgut (insects)  LI (mammals) about 1.5 meters average  Lack plicae, villi, or micro-villi  H2O absorbed through epithelium  Functions  H2O absorption (1400 mL/day)  Compacts/ eliminates feces  Wastes  H2O 75%  Inorganic substances 5%  Fat 5%  Undigested protein, bile, dead cells 7%  Roughage (leftover pieces of molecules) 8%  Vitamin synthesis**-by bacteria  Anus  cloaca- chamber receiving the pathways of the reproductive, urinary, and the digestive system  Accessory Digestive Glands (not part of the digestive tube)  Pancreas-  secretes enzymatic juices into the duodenum  used to break down fats, proteins, carbohydrates, and nucleic acids through the pancreatic duct  Liver-  Produces bile- a chemical that digests fat; increases digestive efficiency  Gall bladder- stores bile  How does the body break down food?  Carbohydrates  Polysaccharides broken down into mono and disaccharides  Proteins  Polypeptides broken down into amino acids  Nucleic acids  Nucleotides  Enzymes  Speed up chemical reactions  Occur at biological temperatures  Can be re-used  Very specific  Regulation of Digestion  Hormones  Gastrin-  Increases stomach movement  Released when food is in lower stomach  Speeds up digestion  Secretin Microvilli Villus Villi  Intercalated discs- junction between cardiac muscle fibers  Only in the heart- contraction pumps blood  This is intrinsic contraction- no stimulation from nervous system required  Smooth muscle  Not striated  Involuntary  1 centralized nucleus  Form sheets to make up tissue  Primarily found in walls of internal organs and glands  More information on the skeletal muscle  Muscle fascicles (collection of skeletal muscle fibers bound together by connective tissue)  Skeletal muscle fibers (individual fibers)  Myofibrils (tiny fibers making up a muscle fiber)  Thin and thick filaments (myofilaments)  Contractile proteins  Thick myofilaments- myosin  Thin myofilaments- actin Figure 44.3 page 922  Sarcomere-  Functional unit of skeletal muscle cells  Distance from one Z-line to the next  Shortens during contraction  Contraction  Causes skeletal movement  Previously referred to as “sliding filament” model  Actin are outside (surrounding) myosin filaments Relaxed- actin and myosin don’t interact (see green figure) Contracted- myosin binds to actin and pulls to contract (see red figure) This causes shortening of the sarcomere ENERGY required- high energy bond of third phosphate (P) of ATP Adenosine –(P)-(P)Ξ(P) Muscle cells contain many mitochondria- “powerhouse” of the cell Site of bulk ATP is formed here Requires oxygen for aerobic respiration Chapter 41-43 Nervous System Closely tied with the sensory system  Components of the Nervous System  Central Nervous System (CNS)  Brain + spinal cord  Ratios (compared to body size, humans have the largest brain)  Fish 2:1  Reptile 25:1  Humans 55:1  Peripheral Nervous System (PNS)  All neurons outside of brain and spinal cord and projections  Invertebrates- simple system; the distinction between PNS and CNS difficult to determine  Neurons-  Structural and functional units of nervous system  Function:  Send and receive electrical and chemical signals to and from other neurons throughout the body  All animals except sponges have neurons Z-lineMyosinActin Myosin head- attach to actin filaments and pull  The more complex and large the animal the more neurons are present  Structure:  Soma- cell body; with nucleus and organelles  Dendrites- cytoplasmic membrane “extensions” that receive incoming signals (many of them)  Axons- cytoplasmic extensions that send signals away (usually only one)  Figure 41.2 page 852  Glial cells- “catch all” group  Involved in support  Over 1000 times more numerous that neurons  Oligodendrocytes (CNS) and the Schwann cell (PNS)  Produce myelin sheath- a sheet or coating over axon  Nodes of Ranvier- gaps in the sheath  Microglial cells- remove cellular debris “cleaners”  Astrocytes and radial glial cells  “stem cells”  Can produce more neurons and more glial cells  *Metabolic support*  **Form tracks for migration of neurons during embryonic development**  3 Types of Neurons  Sensory  Detect information from outside world or internal body conditions  “afferent”- transmit to CNS  Motor-  Send signals away from CNS to cause a response  “efferent”  Interneurons  Form complex interconnections between other neurons Figure 41.3 page 853  Reflex arc- involuntary act (see drawing)  Electrical properties only neurons and muscle cells can generate electrical signals  Membrane potential  Membrane is plasma or the “gatekeeper”  Difference in charge between the inside and outside of a neuron  Chemical difference is in ionic concentration  Cell is polarized  Ions and electrical charge move through channels in the membrane  Resting membrane potential Neurons not sending signals  Selectively permeable to cations (+) and anions (-)  The membrane is what maintains imbalances  Inside is more (-)  Outside is more (+)  Anions inside are drawn to cations on the outside  3 Factors contribute to resting potential:  Sodium potassium pump  3 sodium(+) pumped out for every 2 potassium(+) pumped in  Ion specific channels will allow passive ion movement (no energy spent)  Membrane is more permeable to potassium  Potassium channels are most frequently open at resting potential  More negative charged ions are inside the cell  Electro-Chemical gradient Striking knee Stimulus receptor Sensory & interneurons CNS Motor & interneurons Effector Response Flexor muscles + + +- -- Dendrites ++--+ - + +-- - + Axon  When no net movement, opposing forces of electro chem can cause equilibrium (no potassium flow)  Ion movement and chemical movement (potassium)  This is what creates the imbalance (created between inside and outside of membrane)  Neuron signaling  Changes in membrane potential are changes in degree of polarization  Depolarization-  gated channels for sodium movement into cell  becomes more positive  cell less polarized (membrane less negative to surrounding solution)  Hyperpolarization-  Potassium moves out  Becomes less positive  Cell more polarized (membrane more negative to surrounding solution)  **All cells exhibit membrane potential  **Only neurons and muscle cells are excitable  Use of Gated Ion channels  Voltage-gated-- open and close in response to electrical changes  Ligand-(chemical)gated-- open and close in response to chemical changes  Nerve impulse  Nerve- bundle of neurons enclosed by connective tissue  Sent at a frequency “the language of nerves”; higher frequency, more excitation  Sending an impulse  Resting potential-  imbalance between potassium and sodium; imbalance (gradient) in and out of the axon  At rest membrane is selectively permeable to potassium (+); closed to sodium (+) and chlorine (-)  See drawing  K+ is red  Na+ is blue  Cl- is yellow  Large black line is the plasma membrane  Left side is the extracellular fluid; right side is within the axon  Action potential  Rapid/brief change of nerve fiber  “electric potential” of impulse  It is self-propagating (once it starts it keeps going)  After passing, membrane returns to resting potential  At a given point sodium channels open up and diffuse into axon, and potassium diffuses out due to electrical gradient  Sodium Potassium pump  Complex of proteins embedded in membrane (the pumping system)  Pump out sodium  Pump in potassium  This requires ATP expenditure (3 sodium: 1 potassium)  Impulse conduction rate  It is variable  Ex. Anemone- 0.1 m/s; mammals 120 m/s  Invertebrates- speed is directly related to axon diameter  Vertebrates- speed directly related between axon diameter and layers of myelin sheath  Synapses  Involved in transmission of message  Junction or gap where a nerve terminal end meets a neuron, muscle cell, or gland 30 x more K inside10 x more Na outside 5 X more Cl