Please enable JavaScript.

Coggle requires JavaScript to display documents.

Defense Against Disease, Humoral Immunity, Photosynthesis, Neural…

- - - - 3 layers of skin seal the body
        
        Epidermis
        
        Surface layers
        
        outer cells are dead and packed with keratin: tough, waterproof, difficult for microbes to penetrate
        
        Sebaceous glands open into this area releasing oily secretions
        
        lowers pH of skin: inhibiting bacterial growth on surface
        
        Dermis
        
        Thick layer beneath epidermis containing connective tissue. Supports epidermis.
        
        Contains blood vessels, sweat glands, and houses sebaceous glands
        
        Sweat: contains lysozyme enzyme that digests bacterial cell walls
        
        Hypodermis
        
        bottom layer of the skin storing fat and energy
    - - Stomach Acid
        
        Gastric Secretions contain hydrochloric acid
        
        Destroys most ingested microbes via low pH environment
      - Commensal Bacteria
        
        Found on skin, gut, mouth, and nasal passages
        
        Competes with pathogens for space and nutrients, non specific microbial defense
      - Mucous Membranes
        
        Line all body openings (respiratory, digestive, etc).
        
        Produce Mucus
        
        Contains lysozyme enzymes to break bacterial walls
        
        Then removes mucus + broken down pathogen by cilia, sneezing, coughing, tears, urine.
        
        Traps pathogens
  - - - Phagocytosis
        
        Mechanisms
        
        Exocytosis
        
        Digestive enzymes break down pathogen into small harmless fragments
        
        Process by which digested debris packaged into small vesicles, moves to cell membrane and is expelled
        
        Engulfment
        
        Formation of pseudopodia that encircle target.
        
        Enclose it in membrane bound vesicle called phagosome
        
        Maturation
        
        1 more item...
        
        Digestion
        
        Recognition
        
        Phagocyte recognizes existence of pathogen in vicinity via surface receptors
        
        Phagocyte receptors bind to pathogen antigens
      - Professional Phagocytes: Specialized leukocytes (WBC)
        
        Macrophages, Neutrophils, Monocytes
        
        Amoeboid Movement
        
        Can migrate from blood to site of infection
    - - When the physical skin barrier is breached, the body wants to seal the wound rapidly to prevent further pathogen entry.
        
        Activation of Blood Clotting
        
        Accumulation of platelets at injury site begins. Forming a plug at the injury site.
        
        The platelets and injured tissue then release clotting factors such as calcium ions
        
        Clotting factors then:
        
        Thromboplastin (plasma protein)
        
        1 more item...
- - - - Produced in Bone Marrow
        
        Developing
        
        Maturation
        
        Thymus
        
        T-Lymphocytes
        
        Helper T
        
        1 more item...
        
        Cytotoxic T
        
        2 more items...
        
        Bone Marrow
        
        B-Lymphocytes
        
        Either circulate or concentrate in lymphoid organs
        
        Activation
        
        1 more item...
      - Type of leukocyte
    - - Lymph: watery fluid derived from blood
- - - - Retrovirus (virus with RNA genetic material)
        
        Replicates in human cells by synthesizing DNA from its RNA template via reverse transcriptase
        
        weakens immune system
        
        Attacks helper T cells especially in the gut
        
        Replicates in helper T cells using host infrastructure leading to lysis of T cell
        
        Decreases number of helper T cells. Decreases activation of Cytotoxic T and B cells
        
        Stage 1. Acute HIV infection
        
        4 more items...
        
        Now in Stage 2. Chronic HIV infection. Low multiplication of HIV and no obvious symptoms
        
        1 more item...
      - Acquired via sexual transmission, transfusions, organ transplants, Needles, Childbirth, Breastfeeding. (via bodily fluids)
      - ART: Antiretroviral therapy can lower viral load and slow progression of HIV
- - - - Inhibits growth or replication of pathogen
    - - Directly kills pathogen
  - - - can target many different pathogens. often used when unable to determine specific one
        
        Resistance
        
        Via NS. Strains of bacteria pass on favorable traits that increase resistance to antibiotics.
        
        Over time resistant population increases
        
        Overuse/misuse of antibiotics increases the rate of resistance
        
        many strains have become multi drug resistant
  - - - Targeting
        
        Protein Synthesis Machinery
        
        Cell Wall Synthesis
        
        DNA replication or metabolic pathways
- - - - Inactivated vaccines: inactivated form or killed parts of pathogen
      - DNA: plasmis introduce gene encoding antigen for pathogen, DNA sequences is transcribed, translated, results in antigen produced and gets immune response
      - Live attenuated: weakened form of whole pathogen
      - RNA: same as DNA but RNA
- - - - Non-Cellular
      - Need host, Always pathogenic obligate parasites
      - Ex: Covid-19, Cold, Flu, Measles
    - - Unicellular, Prokaryotic
      - Found everywhere, most are harmless or helpful. Only small % are pathogenic
      - Ex: Tuberculosis, plague, cholera
    - - Uni or Multicellular, eukaryotic. Increasingly common and resistant to treatment. Only some are pathogenic
      - Ex: Ringworm, athletes foot
    - - Mostly unicellular, eukaryotic
      - Diverse group. Pathogenic protists are usually unicellular
      - Ex: Malaria, toxoplasmosis
    - - Proteinaceous (not cells)
      - Mis-folded proteins causing neurodegenerative diseases.
        
        Ex: Mad Cow
    - - Prokaryotic
        
        No known human pathogens
- - - - Photolysis of water
        
        Spurred by loss of electrons from chlorophyll getting in contact with light
        
        Photolysis is the process by which water molecules are split using light energy into:
        
        Electrons
        
        Replace lost
        
        Oxygen
        
        released
        
        Equation for photosynthesis: Carbon Dioxide + Water --> via light --> glucose + oxygen
        
        Hydrogen is gained from water split by photolysis, combined with carbon dioxide to produce glucose, oxygen is a byproduct
        
        Photolysis Equation: 2H20 + Light Energy --> 4H+ + 4e- + O2
        2 Water combined with light leads to 4 hydrogen, 4 electron, 1 oxygen
        
        1 more item...
        
        Hydrogen
      - Generation of ATP
- - - - Contains nucleus, lacks centrioles (no mitosis)
    - - Branched fibers that receive incoming signals
    - - Long fiber for outgoing impulses, starts at axon hillock, ends at axon terminals
    - - Formed by Schwann cells (PNS) / Oligodendrocytes (CNS)
        
        Insulates and speeds up transmissions
        
        Nodes of Ranvier
        
        Gaps that allow jumping of signals (saltatory conductions)
  - - - No Myelin Sheath because generally are short
  - - - Maintained and controlled by transmembrane protein sodium-potassium pumps
        
        Expels 3 sodium (Na+) for every two potassium (K+) ions admitted
        
        As there are more positively charged ions outside the cell, the inside is relatively negative.
        
        Requires the hydrolysis of ATP
  - - - Speed is not constant.
        
        Larger organisms tend to have slower conduction speeds due to more complex neural pathways with more synaptic gaps causing delays in transmission
        
        How to increase speed
        
        Wider diameters of axons due to less longitudinal resistance
        
        Results in speeds slower than myelinated axons
        
        Insulated via myelin sheaths as nodes of ranvier lead to less points requiring generation of action potentials, increasing flow of current
        
        But takes up space and requires ATP which may outweigh benefits.
- - - - Triggered by opening of sodium and potassium channels along the axon
        
        Positive charge ions move along conc gradients established by resting potential creating electrical charge
        
        Sodium ions move FIRST
        
        Move into the neuron to create a positive membrane potential (depolarisiation). BEFORE potassium flows out.
        
        Potassium ions then move out to re-establish a negative membrane potential (repolarization)
        
        Once action potential has occurred, resting potential must be restored by sodium potassium pumps brining potassium back inside and sodium out, before this can happen again (refractory potential)
- - - - Therefore, to transmit information, electrical signals need to be converted into chemical signals (called neurotransmitters)
        
        In order to transmit information across synapses, the release of neurotransmitters from the pre-synaptic neuron to the post-synaptic neuron needs to occur.
        
        When an action potential reaches its axon terminal --> triggers opening of voltage gated calcium channels from axon to extracellular environment
        
        Calcium ions diffuse into the cell and promote the fusion of vesicles (containing neurotransmitters) with the cell membrane
        
        The neurotransmitters are released from the axon terminal by exocytosis and diffuse across the synaptic cleft
        
        The neurotransmitters then bind to specific receptors on the post-synaptic membrane and open ligand-gated ion channels
        
        1 more item...
        
        Neurotransmitters as chemical messengers
        
        Released in response to change in membrane potential at axon terminal of a presynaptic neuron
        
        Can bind to receptors on post-synaptic cells and trigger response by causing a change in membrane potential
        
        Response in muscles:
        
        trigger the contraction or relaxation of muscle tissue (stimulating movement)
        
        Response in glands:
        
        trigger the release of chemicals (hormone release from endocrine gland cells)
        
        Response in Neuron:
        
        trigger propagation of action potential in next neuron (continuing nerve impulse)
        
        Acetylcholine as a commonly used neurotransmitter. Used by both CNS and PNS
        
        Commonly released at neuromuscular junctions. Binds to receptors on muscle fibers to trigger voluntary muscle contractions.
        
        Also commonly released within autonomic nervous system to promote parasympathetic responses.
        
        Autonomic = regulatory of involuntary bodily processes
        
        Created in the axon terminal by combining choline with an acetyl group
        
        Stored in vesicles until released via exocytosis in response to nerve impulse
        
        1 more item...
        
        Must be continually removed from synapse after activation occurs, as overstimulation can lead to fatal convulsions and paralysis
        
        Broken down by enzymes that are either released into synapse by presynaptic or embedded in membrane of post synaptic
        
        1 more item...
- - - - Small molecule that stores and transfers energy in cells
      - Structure
        
        Adenine
        
        Three phosphate groups
        
        Ribose
      - How does it work.
        
        The bond between the 2nd and 3rd phosphate is unstable and can be broken to release energy
        
        ATP --> ADP and an inorganic phosphate
        
        ATP --> ADP + Pi
        
        Hydrolysis reaction, exergonic reaction (releases energy from bond breakage)
        
        Powers:
        
        Active Transport
        
        Cytoskeleton Movement
        
        Muscle Contraction
        
        Protein Synthesis
    - - All living cells both pro and eukaryotic
    - - Provides energy to drive cellular processes like transport, synthesis, movement, and repair
    - - To regenerate ATP, a phosphate group is added to ADP to become ATP.
        
        requires energy input, endergonic
        
        Most common fuel in cellular respiration is glucose
        
        also lipids, proteins
        
        Done via Cellular Respiration which has two types
        
        Aerobic Respiration
        
        The process by which cells break down glucose in the presence of oxygen to produce large amounts of ATP
        
        High ATP yield, 36-38 ATP per glucose
        
        Waste products: CO2, H20
        
        Starts in Cytoplasm, continues in mitochondria
        
        Used most of the time, when normal oxygen conditions apply
        
        Uses Oxygen
        
        Anaerobic Respiration
        
        The process by which cells break down glucose WITHOUT oxygen to produce large amounts of ATP
        
        Low yield 2 ATP per glucose
        
        Lactic acid (lactate)
        
        Only in the cytoplasm
        
        When oxygen is low (e.g. intense exercise)
        
        Occurs without oxygen
        
        Cellular respiration releases energy from food molecules, that energy is then used to create ATP from ADP and Pi (phosphorylation).
        
        The energy from food molecule degredation cannot be used to power processes. It must be in ATP form, so the energy released gradually from food molecules breaking down is used to charge ATP by forming a bond between phosphate 2 and 3, storing actable energy for cellular processes.