Please enable JavaScript.

Coggle requires JavaScript to display documents.

Chapters 42-43 - Coggle Diagram

- - - - Barrier defenses
        
        Chitin in insects
        
        Exoskeletons, lines the intestines
        
        Lysozyme - enzyme that breaks down bacterial cell walls
    - - Take action when barriers are breached
      - Invertebrates
        
        Recognition proteins in insects
        
        Bind to molecules from a broad class of pathogens
        
        Triggers innate immune response
        
        (Anything not normally found in animal cells)
        
        Major immune cells in insects are hemocytes
        
        Some are phagocytic
        
        Some release antimicrobial peptides
        
        Responses are specific to particular classes of pathogens
        
        Ex.) binding to a fungal cell wall activates Toll
      - Vertebrates
        
        Coexist with adaptive immunity
        
        Barrier defenses
        
        Mucous membranes
        
        Line digestive, respiratory, urinary, and reproductive tracts
        
        Saliva, tears, mucous secretions "wash" away pathogens
        
        Also contain lysozyme
        
        The skin
        
        High pH in the stomach and on the skin
        
        Cellular defenses
        
        Toll-like receptors bind to fragments of molecules characteristic of a set of pathogens
        
        Two most common are macrophages and neutrophils
        
        Neutrophils - circulate in the blood and are attracted by signals
        
        Macrophages - larger phagocytic cells, migrate or stay put where pathogens are more likely to be
        
        Other specialized cells:
        
        Dendritic cells - populate tissues that contact the environment
        
        1 more item...
        
        Inflammatory response
        
        Events triggered by signaling molecules upon injury or infection
        
        Begin when activated macrophages secrete cytokines; recruit neutrophils
        
        Mast cells release histamine; triggers nearby vessels to dilate
        
        This produces the redness and warm sensation
        
        Allows for more antimicrobial peptides and good stuff to reach the site
        
        Interferons are secreted by infected cells to get help from other cells
        
        Pus forms from accumulated white blood cells, dead pathogens, and debris
        
        Once over, fluids and pus are taken up as lymph
        
        Macrophages in lymph nodes engulf anything left
        
        Systemic inflammation results in fever
        
        Chronic inflammation disrupts other bodily processes
    - - Can change their epitopes
      - Mutations can go undetected by memory cells
      - Latency within cells
        
        Viruses infect but pause on production
        
        Resume during favorable conditions
        
        Viral genome persists, even if inactive
  - - - Pathogen specific recognition
      - Humoral response
        
        Antigens defend against infection in body fluids
        
        Binding of a B cell to an antigen leads to secretion of antibodies, or immunoglobulin
        
        Direct defense against pathogens
        
        Bind to epitopes of intact antigens
      - Cell-mediated response
        
        Cytotoxic cells defend against infection in body cells
        
        Toxic proteins kill infected cells; require signals from helper T cells
        
        T cells only bind to fragments of antigens that are displayed on host cells
        
        The protein that displays the fragments are MHC moelcules
      - Slower response
      - Relies on T cell and B cell lymphocytes
        
        T cells migrate from the bone marrow to thymus
        
        B cells mature in the bone marrow
        
        Anything that elicits their response is an antigen
      - LOTS of receptors, self tolerance, cell proliferation, memory
        
        Lots of possible allele combinations for antigen receptors
        
        As lymphocytes mature, their tolerance is tested on
        
        Are eliminated or rendered nonfunctional if their receptors match the body's own molecules
        
        When activated, B and T cells make lots of copies
        
        Effector cells are short lived and made to fight
        
        Memory cells are long term and can give rise to the same effectors for next time
        
        Primary immune response - effector cells after an initial response to an antigen
        
        Secondary immune response - faster response when antigen is encountered again
      - Memory cells are why immunizations work
      - Active immunity arises when a pathogen prompts a response
      - Passive immunity is when antibodies are produced by someone else
  - - - As long as its receptors can bind to the antigen, and is displayed on an antigen-presenting cell
    - - Opsonization marks them for other macrophages and neutrophils
      - Neutralization prevents viral infection
  - - - Type 1 diabetes, MS, lupus
      - Regulatory T cells thought to play a role
      - Exertion and stress can negatively impact the immune system
      - HIV infects helper T cells
    - - Inborn from genetic or developmental defects
      - Acquired from exposure to chemicals or biological agents like AIDS, cancer
- - - - Circulatory system
        
        Closed circulation
        
        Blood is the circulatory fluid and is confined to blood vessels
        
        Exchange occurs between interstitial fluid and blood
        
        As well as interstitial fluid and body cells
        
        High enough blood pressure for bigger, more active animals
        
        Suited for delivery to different organs
        
        Open circulation
        
        Hemolymph is the circulatory and interstitial fluid, and constantly bathes body cells
        
        Molluscs, arthropods
        
        Use less energy
        
        Consists of a circulatory fluid, interconnecting vessels, and a heart
        
        Optimal for bigger and complex animals
      - Simple body plans
        
        Unicellular organisms exchange directly with environment
        
        Cniderians utilize a gastrovascular cavity
        
        Opening connects cavity to environment
        
        Fluid bathes all tissues, facilitating exchange in the process
        
        Nutrients can diffuse easily through body wall
        
        Places all or most cells in direct contact with environment
        
        Flat shapes (such as flatworms) optimizes exchange
        
        Increases surface area and minimizes diffusion distances
    - - Exchange surfaces need to be thin with a large surface area
      - Gasses gravitate to low concentrations
  - - - Blood flows in one direction
        
        Arteries carry blood away from the heart
        
        Arteries branch into arterioles
        
        Convey blood to capillaries
        
        Flow into capillary beds
        
        Converge into venules
        
        1 more item...
        
        Exchange occurs
      - NOT defined by oxygen content
      - Portal veins carry blood between two capillary beds
    - - Contain two or more chambers
        
        The ventricles pump blood out
        
        The atria receive blood
      - Single circulation
        
        Blood travels through the body and returns in a single loop
        
        In sharks, rays, bony fishes
        
        Gill capillaries and body capillaries
      - Double circulation
        
        Blood flows through two circuits
        
        In amphibians, reptiles, mammals
        
        Amphibians and reptiles have a 3 chambered heart
        
        2 atria, 1 ventricle
        
        Their ventricles are partially divided by a septum
        
        Birds and mammals have a 4 chambered heart
        
        2 atria, 2 ventricles
        
        4 chambers are needed because they're endothermic and/or large in size
        
        More cells and tissues need more oxygen
        
        More cells and tissues also produce more waste
        
        Pulmonary and systemic circuit
        
        Pulmocutaneous circuit and systemic circuit
        
        Steps of mammalian circulation:
        
        Right ventricle contracts and pumps blood out of the heart via pulmonary arteries
        
        Deoxygenated blood travels to the lung's capillaries
        
        Gas exchange occurs, the now-oxygenated blood flows to the left atrium
        
        Blood flows into the left ventricle
        
        1 more item...
    - - Atria have thinner walls, most blood flows to the ventricle during relaxation
      - Ventricles have thicker walls and contract more forcefully (especially the left because it sends blood to the pulmonary circuit)
      - When the heart contracts, it pumps blood
        
        Systole
      - When the heart relaxes, chambers fill up
        
        Diastole
      - Cardiac output - volume of blood each ventricle pumps per minute
        
        Determined by heart rate (bpm) and stroke volume (amount of blood pumped by a ventricle in a single contraction
      - 4 valves facilitate blood flow
        
        2 semilunar valves
        
        located at the 2 exits
        
        2 atrioventricular valves
        
        Between each atrium and ventricle
        
        Backflow produces a heart murmur
      - Sinoatrial node acts as a pacemaker
        
        Located in the wall of the right atrium
        
        Produces electrical impulses
        
        Can be measured with an electrocardiogram
        
        Impulses are delayed before spreading to the apex in the atrioventricular node
        
        Sympathetic and parasympathetic systems can alter this tempo
  - - - Arteries
        
        Endothelium, thick smooth muscle, thick connective tissue
        
        Thick, strong, and elastic to withstand higher blood pressure
        
        Maintains blood pressure and flow to capillaries
      - Veins
        
        Endothelium, thinner smooth muscle, thinner connective tissue, valves
        
        Thinner than arteries because they carry blood to the heart; lower pressure
        
        Valves maintain unidirectional flow
      - Capillaries
        
        Endothelium, basal lamina
        
        As wide as one red blood cell
        
        Very thin walls for exchange between blood and interstitial fluid
        
        Constant blood supply with the brain, heart, and kidneys at full capacity
        
        Blood supple is diverted away from organs that don't need as much
        
        Redirection is possible with sphincters
        
        Small molecules can diffuse across the endothelium
        
        Bigger molecules by endo- and exocytosis
        
        Blood pressure drives fluid out of capillaries
        
        Osmotic pressure brings fluid in capillaries
      - Smooth muscle regulate the path of blood flow
        
        Signals to these muscles trigger constriction and dilation
    - - Blood flow is the quickest in the aorta, slows down in the arteries and arterioles
        
        Flows VERY slowly through the capillaries, speeds up continously as they branch into the venules, veins, and venae cavae (but not as fast as the aorta)
    - - Blood pressure is the highest in the aorta, and dissipates from there
        
        Systolic pressure
        
        Blood pressure during ventricular contraction
      - Diastolic pressure
        
        Blood pressure during ventricular relaxation
      - Pressure and gravity
        
        "Normal" blood pressure: 120/70
        
        Always systole/diastole
        
        Changes in body positions change pressure and blood flow to those areas
        
        When standing, blood pressure is lower in the head than closer to the heart
        
        Fainting puts the head closer to the heart, increasing blood flow
        
        Standing/sitting draws blood flow downward
        
        Blood can pool in legs because of the lower pressure
        
        Smooth muscle can contract when skeletal muscles contract (aka when you move around)
        
        Allows blood to be drawn upwards back to the heart
    - - Recovers and returns lost fluid from capillaries
        
        Fluid is originally blood plasma, becomes interstitial fluid when it;s leaked, and lymph when picked up
        
        If fluids are not picked up, they accumulate and cause swelling (edema)
      - Lymph circulates in the lymphatic system, and drains into a large pair of veins at the base of the neck
        
        Exchange occurs
      - Lymph vessels have valves, and their walls contract
      - Lymph nodes - small, lymph-filtering organs
        
        Filled with white blood cells
  - - - Plasma
        
        Blood's liquid matrix of dissolved ions and proteins
        
        Ions that leak into interstitial fluid go to muscles and nerves
        
        Proteins make up antibodies, apolipoproteins to escort lipids, and fibrinogens for clotting
        
        Osmotic regulation, transport, defense
      - Cellular components
        
        Erythrocytes
        
        Transport oxygen
        
        Contain hemoglobin; the iron containing proteins that carry oxygen
        
        Are anaerobic
        
        When oxygen is low, kidneys produce erythropoietin (EPO) to make more
        
        Can treat anemia, and popular in athletes
        
        Leukocytes
        
        Fight infections
        
        Some are phagocytic and some are lymphocytes
        
        Can be found outside the circulatory system
        
        Platelets
        
        Fragments of specialized bone marrow cells
        
        Clotting
        
        Coagulation; conversion of the liquid components into a solid
        
        When clotting factors are released, prothrombin is activated into thrombin, and activates fibrinogen to fibrin
        
        Mutations hat affect this can result in hemophilia
        
        All develop from stem cells
        
        Continuously replenish blood cells
    - - Atherosclerosis
        
        Accumulation and hardening of fatty deposits in arteries
        
        Damage to arterial linings cause inflammation
        
        Leukocytes attend inflamed area and take up lipids, including cholesterol which gives membranes their fluidity
        
        Causes plaque to grow and can obstruct arteries
      - Heart attacks
        
        Death of cardiac tissue limiting oxygen supply to the heart
      - Stroke
        
        Death of nervous tissue from lack of oxygen
      - Risk factors
        
        High ratio of LDL to HDL
        
        LDL delivers cholesterol to cells, HDL scavenges the extra
        
        Statins can lower LDL
        
        Smoking can worsen this
        
        Hypertension is though to damage endothelium
      - Thrombus - blood clots within blood vessels
- - - - More oxygen in the air than water
      - Water is more demanding than air
        
        Lower oxygen, greater density and viscosity
        
        Requires more energy
      - Animals have adapted to their respiratory media
    - - Gills
        
        Outfoldings of the body surface suspended in water
        
        When water moves over the gills: ventilation
        
        Maintains partial pressure gradients
        
        Animals can move their gills through the water or move water over their gills
        
        Crayfish and lobsters use appendages to move water over their gills
        
        Octopuses and squid take in water and eject it
        
        Fish use the motion of swimming and operculum
        
        Exchange maximized by countercurrent exchange
        
        Blood and water flow in opposite directions
        
        In fish
      - Tracheal systems
        
        In insects
        
        When certain insects fly, more oxygen is needed and is consumed because the act of flying allows more air to enter the tracheae
        
        Internal network of air tubes throughout the body, with trachea that open to the outside (largest tubes)
        
        Gas exchange occurs at the tips of the smallest branches
        
        Separate from open circulatory system
      - Lungs
        
        Localized respiratory organs. An infolding of the body surface subdivided into pockets
        
        Because they are localized, they work together with the circulatory system
        
        Found in amphibians, reptiles, and mammals
      - Closer look at mammalian lungs
        
        Lungs located in the thoracic cavity; enclosed by ribs and diaphragm
        
        Air enters through nose, goes through the pharynx, passes the larynx to get into the trachea
        
        Trachea branch into two bronchi, one for each lung
        
        The bronchi branch repeatedly into bronchioles
        
        Gas exchange occurs in alveoli
        
        3 more items...
        
        Mucus is produced to keep out contaminants
        
        1 more item...
        
        Air passing through vocal folds produce sounds
    - - Sponges, cnidarians, and flatworms are able to directly exchange with the environment
        
        More complex bodies need respiratory surfaces
        
        Increase surface area
  - - - Ventilate with positive pressure breathing
        
        Inflating the lungs with forced air flow
        
        Muscles lower the floor of the mouth
        
        Air enters through nostrils
        
        Floor of the mouth rises, in doing so pushes air into the trachea
        
        Exhalation by elastic lung recoil and compression of muscular body wall
    - - Air passes over exchange surface in one direction
      - They have parabronchi, air sacs, and lungs
        
        Parabronchi serve as the gas exchange sites
      - Requires two cycles of inhalation and exhalation
        
        Air fills posterior air sacs
        
        Posterior air sacs contract and push air into the lungs
        
        Air passes through lungs and fills the anterior air sacs
        
        Anterior air sacs contract, pushes first inhalation out of the body
      - Air is pushed through with more air
    - - Negative pressure breathing
        
        Pulling air into the lungs
      - Contraction of the diaphragm expands the thoracic cavity
        
        Increases volume and decreases pressure in the lungs
        
        Air flows from areas of higher to lower pressure; so, it is pulled into the lungs during exhalation
        
        Exhale, and diaphragm relaxes, increasing the pressure
        
        Air is directed out
      - Tidal volume - volume of air inhaled and exhaled with each breath
      - Vital capacity - tidal volume during max inhalation and exhalation
        
        Residual volume - any remaining air following exhalation
        
        Lungs work because partial pressure of oxygen is higher in the environment; which is why it's harder to breathe at high altitudes
    - - Neurons mainly responsible: in medulla oblongata
        
        Medulla increases depth and breath rate when its fluid's pH is low
        
        Carbon dioxide in the blood diffuses into cerebrospinal fluid, reacts with water, and forms carbonic acid
        
        Carbonic acid disassociates into a bicarbonate and hydrogen ion
        
        As hydrogen ions increase, pH lowers
        
        Aorta and carotid arteries detect low oxygen levels, and send signals to breathing control centers
        
        Neural circuits in medulla oblongata form breathing control centers that establish breathing rhythm
  - - - Proteins that oxygen binds to and circulates with blood/hemolymph in specialized cells
      - Useful because of the low solubility of oxygen in water
        
        Increase the amount of oxygen that can circulate
      - Usually consist of a metal bound to a protein
        
        The metal is copper in hemocyanin in arthropods and molluscs, giving them blue blood
        
        Most vertebrates have hemoglobin, where the metal is iron
        
        Contained in erythrocytes
        
        4 subunits of a polypeptide and heme group (cofactor with 1 iron in center)
        
        Bohr shift - low pH decreases affinity of hemoglobin for oxygen
        
        Hemoglobin releases more oxygen
        
        Hydrogen ions can also bind to hemoglobin, and act as a buffer
    - - Weddell seal, Cuvier's baked whale
      - Capacity to store large amounts of oxygen, usually in myoglobin
      - Abilities to conserve oxygen
        
        Don't move much
        
        When diving, blood is directed to vital tissues
        
        During a dive, they use oxygen stored in their myoglobin and derive ATP from fermentation
    - - During inhalation, fresh air mixes with leftover air in the lungs
        
        Mixture in alveoli has higher partial pressure of oxygen than blood flowing in alveolar capillaries
        
        Air diffuses from alveoli into the blood
        
        Partial pressure of carbon dioxide is higher in alveoli and capillaries, so it diffuses from the blood into the air
        
        When blood leaves the lungs, its partial pressures for oxygen and carbon dioxide match with the alveoli
        
        This blood is pumped through the systemic circuit, where partial pressure gradients favor diffusion of oxygen out of the blood, and carbon dioxide into the blood
        
        1 more item...