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DavidRascon40-41.pdf - Coggle Diagram

- - - - Macronutrients: carbohydrates, lipids, proteins
      - Cellular respiration/fermentation
      - Fates of nutrients: immediate oxidation, storage
      - Heat loss at each step
    - - Used for biosynthesis: macromolecules, growth/repair, reproduction
    - - Essential amino acids
        
        nimals can synthesize
        
        Adults need 8: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine
        
        Infants also need histidine
        
        Complete proteins: animal foods (meat, eggs, dairy)
        
        Incomplete: most plant proteins (corn low, beans low in Met)
      - Essential fatty acids
        
        Needed for membrane phospholipids, signaling molecules, storage fats
        
        Lacking enzymes to add certain double bonds
      - Vitamins
        
        Water-soluble: B-complex (coenzymes like FAD/NAD⁺), C (
        
        Fat-soluble: A (visual pigments), D, E (antioxidant), K (clotting)
        
        D can be synthesized in skin with sunligh
      - Minerals (inorganic, small amounts)
        
        Major functions: enzyme cofactors, osmotic/acid–base balance, nerve/muscle function, bone structure, hormones
        
        Ca, P
        
        Na, K, Cl
        
        Fe
        
        F
    - - Herbivores, carnivores, omnivores (humans typically omni/herbi)
      - Most animals are opportunistic feeders (flex when usual food scarce)
      - Microbes are an unavoidable “supplement” in every diet
    - - Essential nutrient deficiency → deformities/disease
      - Protein deficiency (common in humans) → impaired physical/mental development
      - Undernourishment (low energy intake)
    - - Humans vary genetically/environments
      - Case study folic acid supplementation in grains → reduced neural tube defects
      - Species differences: some synthesize vitamin C humans must eat it
  - - - Feeding mechanisms
        
        Filter/Suspension feeding: strain particles from water
        
        Substrate feeding: live in/on food source
        
        Fluid feeding: suck nutrient-rich fluids
        
        Bulk feeding: eat large pieces/whole prey
    - - Mechanical digestion:
        
        chewing, grinding, churning
      - Chemical digestion
        
        Carbs: polysaccharides/disaccharides → monosaccharides
        
        e.g., sucrase: sucrose → glucose fructose
        
        Proteins → peptides → amino acids
        
        Nucleic acids → nucleotides → bases/sugars/phosphate
        
        Fats/phospholipids
    - - Cells take up small molecules
    - - Undigested material exits the digestive system as feces
    - - Intracellular digestion
        
        Food vacuoles form phagocytosis/pinocytosis
        
        Vacuoles fuse with lysosomes → hydrolytic enzymes digest safely inside
        
        Seen in sponges
      - Extracellular digestion
        
        Hydrolysis in compartments continuous with outside
        
        Gastrovascular cavity
        
        Gland cells secrete enzymes into cavity (start extracellular digestion)
        
        Food breaks into particles
        
        Gastrodermis cells engulf particles → finish intracellularly
        
        Undigested remnants expelled back through mouth
      - Alimentary canal / complete digestive tract
        
        One-way flow through specialized compartments for sequential processing
        
        Can ingest new meal while prior meal is still being digested
        
        Typical of most animals
  - - - Salivary glands
        
        Mucus
        
        Amylase
      - Pancreas → bicarbonate, proteases, amylases, lipase, nucleases
      - Liver → makes bile
      - Gallbladder → stores/concentrates bile
    - - Teeth: cut/mash/grind tongue shapes bolus
      - Swallowing reflex: epiglottis closes trachea esophageal sphincter opens
      - Peristalsis propels bolus sphincter at stomach entry regulates passage
    - - Gastric juice = HCl (very low pH)
        
        HCl: disrupts ECM, denatures proteins
        
        Pepsin (protease)
      - Gastric glands
        
        Parietal cells
        
        Chief cells: pepsinogen
        
        Mucous cells: mucus protects lining
      - Churning
      - Lining renewal prevents self-digestion
    - - Duodenum
        
        Chyme + pancreatic juice + bile + intestinal enzymes
        
        Hormonal control: secretin
        
        Proteases secreted inactive → activated safely in lumen
        
        Fats: bile salts emulsify → lipase → fatty acids + monoglycerides
      - Jejunum/Ileum
        
        Huge surface area: circular folds
        
        Transport
        
        Fructose: facilitated diffusion
        
        Glucose, amino acids, vitamins, many peptides: active transport
    - - T-shaped junction
      - Colon: completes water recovery
      - Rectum: stores feces
  - - - Carnivores (cats/dogs): large incisors/canines , sharp premolars/molars slice & shred
      - Herbivores (deer/horse): broad, ridged premolars/molars grind cellulose diastema gap incisors clip vegetation
      - Omnivores (humans): mixed set incisors (bite), canines (tear), premolars/molars (crush)
    - - Carnivores: often large, expandable stomachs
      - Herbivores/omnivores: longer alimentary canals
        
        More time & surface area for digestion/absorption
        
        Koala: very long intestines enlarged cecum/colon for leaf fermentation
        
        Carnivores: shorter intestines, smaller cecum
    - - Human gut: trillions of microbes mutualism
      - Stomach health example
        
        Helicobacter pylori infection → stomach community becomes near-monocultur
      - Therapies
        
        Fecal microbiota transplant
        
        Bacteriophages
    - - Problem: animals lack cellulase
      - Solution: fermentation chambers house microbes that digest cellulose
    - - 4 chambers: rumen + reticulum (microbial cellulose digestion) → cud regurgitated and rechewed → omasum (water removal) → abomasum
  - - - Neural control
        
        Enteric nervous system: local reflexes coordinate secretion & motility along the gut
    - - Gastrin (from stomach when stretched) → gastric juice secretion
      - Secretin (from duodenum to pancreas) → to neutralize chyme
      - CCK (from duodenum to pancreas/gallbladder) → digestive enzymes & bile release
      - Fat-rich chyme
    - - Where energy goes
        
        Glycogen
        
        Triglycerides (adipose)
      - When intake < expenditure
        
        Muscle uses its glycogen
        
        Liver/adipose release glucose & fatty acids to blood
        
        Fat oxidation
    - - High glucose → Insulin
        
        cellular uptake of glucose
        
        Liver: glucose → glycogen
      - Low glucose → Glucagon
        
        Liver: glycogenolysis & gluconeogenesis
      - Diabetes
        
        Type 1 (insulin-dependent): autoimmune
        
        Type 2 (non-insulin-dependent): insulin resistance
    - - Satiety center (brain) integrates hormonal signals
        
        Appetite stimulant: Ghrelin
        
        Appetite suppressants:
        
        Insulin (post-meal)
        
        PYY (small intestine, post-meal counters ghrelin)
        
        Leptin
      - Classic mouse genetics (parabiosis)
        
        ob/ob mice lack a circulating satiety hormone → become obese
        
        db/db mice lack the hormone’s receptor → cannot respond; overproduce hormone
        
        Parabiosis results
        
        WT + ob/ob → ob/ob loses weight
        
        WT + db/db or ob/ob + db/db → WT/ob become hypophagic/lose weight
- - - - Physical laws limit designs
        
        Support/locomotion constraints scale with size
        
        Larger bodies - thicker skeletons required
      - Surface area volume (SA:V) rules exchange
        
        Small/flat bodies → high [SA:V]
        
        Amoeba single cell membrane handles exchange
        
        Hydra 2 cell layers + gastrovascular cavity
        
        Tapeworm extreme flatness, direct nutrient contact
        
        Large, compact bodies → low SA:V
        Need specialized internal exchange surfaces
        
        Branching/folding massively increase area
        
        Digestive: intestinal villi/microvilli → nutrient absorption
        
        Respiratory: alveoli (spongy) → O₂/CO₂ exchange
        
        Excretory: kidney nephrons (glomeruli) → waste/solute balance
        
        Circulatory links all exchange surfaces to cells
    - - Cells → Tissues → Organs → Organ Systems
        
        Tissues (4 major types)
        
        Epithelial
        
        Apical side faces lumen/exterior; basal side to basal lamina
        
        Types & functions
        
        Simple squamous → thin, leaky → diffusion (capillaries, alveoli)
        
        Simple columnar → secretion/absorption (intestine)
        
        Cuboidal → secretion (kidney tubules; glands)
        
        Pseudostratified ciliated → mucus escalator (respiratory tract)
        
        Stratified squamous → abrasion resistance (skin, mouth)
        
        Connective
        
        Fibers: collagenous (strength), elastic (stretch), reticular (join)
        
        Loose CT (binds epithelia, holds organs)
        
        Fibrous CT (tendons/ligaments)
        
        Bone (osteons; mineralized matrix)
        
        Cartilage (chondrocytes; chondroitin sulfate)
        
        Adipose (fat storage/insulation)
        
        Blood (plasma + RBCs/WBCs/platelets)
        
        Muscle
        
        Skeletal (striated) → voluntary; multinucleate; sarcomeres
        
        Smooth → involuntary; organs, vessels (peristalsis, vasoconstriction)
        
        Cardiac → striated + intercalated discs; sync contraction
        
        Nervous
        
        Neurons: dendrites, cell body, axon
        Glia: nourish, insulate, modulate neurons
    - - Endocrine system (slow-onset, long-lasting, broadcast)
        
        Hormones in blood → only target cells (specific receptors) respond
        
        Examples: TSH → thyroid; thyroid hormone → ↑ O₂ use & heat
        
        Best for growth, development, metabolism, reproduction, digestion
      - Nervous system
        
        Nerve impulses along axons → precise circuits
        
        Acts on neurons, muscles, secretory cells
        
        Encodes info by pathway activated (e.g., pitch perception)
      - Integration
        
        Systems co-regulate to keep internal conditions stable (homeostasis)
        Example chain: smell cue → brain → muscles & circulation → fuel delivery
  - - - Components: mouth → anus; accessory organs (liver, pancreas)
      - Function: ingestion, digestion, absorption, elimination
    - - Components: heart, blood, vessels
      - Function: distribute gases, nutrients, wastes, signals, heat
    - - Components: lungs, trachea, airways
      - Function: gas exchange (O2 in, CO2 out)
    - - Components: bone marrow, thymus, spleen, lymph nodes/vessels
      - Function: defense vs pathogens, abnormal cells
    - - Components: kidneys, ureters, bladder, urethra
      - Function: nitrogenous waste removal; osmotic regulation of blood
    - - Components: pituitary, thyroid, pancreas, adrenals, etc.
      - Function: hormonal coordination of body activities
    - - Components: ovaries/testes + ducts/glands
      - Function: gametes, fertilization support, embryo support
    - - Components: skin, hair, claws/nails, sweat glands
      - Function: protection; thermoregulation; dehydration barrier
    - - Components: bones, cartilage, ligaments, tendons
      - Function: support; protect organs; leverage for movement
    - - Components: skeletal muscles
      - Function: locomotion & movement
  - - - Regulators vs Conformers
        
        Regulator: uses internal mechanisms to keep a variable near a set point despite external change
        
        Conformer: internal condition follows external change
        
        Mixed strategy: organism may conform for one variable, regulate another
        
        Marine invertebrates conform to stable ocean salinity
    - - Definition: maintenance of a steady internal state within tolerable ranges
      - Human examples
        
        Body temperature ≈ constant
        
        Blood pH
        
        Blood glucose
    - - Set point: desired range for variable
        
        Stimulus: deviation from set point
        
        Sensor: detects change
        
        Control center: processes signal
        
        Response (effectors)
    - - Negative feedback
        
        Definition: response reduces the original stimulus (damps change)
      - Positive feedback
        
        Definition: response amplifies the stimulus
  - - - Endotherms: heat mainly from metabolism
        
        Who: mammals, birds (also some fishes/insects, few reptiles)
        
        Pros: stable Tb in cold/hot environments
      - Ectotherms: heat mainly from environment
        
        Who: most invertebrates, amphibians, many reptiles & fishes
        
        Pros: lower food needs tolerate wider Tb swings
    - - Poikilotherm: Tb varies with environment
      - Homeotherm: relatively constant Tb
    - - Radiation (sun to body)
      - Evaporation (liquid → vapor removes heat)
      - Conduction (direct contact: rock to lizard)
      - Convection (moving air/water; wind, blood flow)
    - - Insulation
        
        Hair/feathers (can raise to trap air), fat/blubber (marine mammals)
        
        Oils preserve insulation (bird preening)
        
        Humans: rely mostly on subcutaneous fat; “goose bumps” = vestigial piloerection
      - Circulatory adaptations
        
        Vasodilation ( raises skin blood flow → raises heat loss by rad/cond/conv)
        
        Vasoconstriction (decreases skin blood flow → conserve heat)
        
        Countercurrent heat exchange (arteries next to veins)
      - Evaporative cooling
        
        Sweating
        
        Mouth pouch flutter in some birds
    - - Posture/orientation/choice of microhabitat
        
        Dragonfly “obelisk” posture minimizes solar gain
      - Social behavior
        
        Penguins huddle (endotherms) to reduce exposure
    - - Shivering
        
        Tiny endotherms (chickadees) maintain Tb in very cold air
        
        Insects warm flight muscles by shivering before takeoff
        
        Pythons (egg-brooding females) can shive
      - Nonshivering thermogenesis
        
        Hormone-driven mitochondrial heat production
        
        Brown fat (neck/shoulders): abundant in infants
  - - - Autotrophs vs Heterotroph
        
        Autotrophs: make organic fuel (photosynthesis)
        
        Heterotrophs (animals): eat organic molecules
    - - Metabolic rate (MR) = total energy use per time
      - How measured
        
        Calorimetry (heat loss)
        
        Gas exchange
        
        Energy budget: food intake − energy in wastes
    - - Minimum Metabolic Rate & Thermoregulation
        
        Humans: males ~1,600–1,800 kcal
      - Ectotherms → SMR
        
        Example: alligator ~60 kcal/day
    - - Whole-animal MR scales with body mass
        
        Holds broadly across taxa
      - Per-gram MR decreases with size
        
        Mouse gram is more than elephant gram
        
        Small animals: higher breathing/heart rate
    - - Activity elevates MR above BMR/SMR
      - Daily energy expenditure
        
        Typical terrestrial animals: 2–4 times BMR
      - Energy budgets
        
        Functions: basal/standard, activity, thermoregulation, growth, reproduction
    - - Thermoregulation costs
        
        Cold climates/endotherms → more energy to maintain Tb
        
        Ectotherms → lower intake; activity windows tied to ambient temp
    - - Torpor = short-term
        
        Small endotherms (bats, chickadees, hummingbirds)
      - Hibernation (winter long-term torpor)
      - Estivation (summer torpor) for heat/drought survival
      - Circadian clock in deep hibernation