Organization of the gut
What are the two levels of organization based on function?
What is in each category?
Basic = self-organization, regulation, support/movement, replication
Specialized = gland cells (that secrete digestive enzymes), neurons (that generate and transmit electrical impulses), muscle cells (produce movement)
What are the limitations of feedback loops? why?
Imperfect anticipation - disruption is inevitable = cannot guess what will happen, your brain does not know to shift your temp ahead of going outside
Delayed responses
What are the building blocks of life? organic vs inorganic?
organic = Carbohydrates, Lipids, Amino acids, Nucleic acids
inorganic = everything else
What do excitable cells? what kinds are there?
neurons, and muscles
evolved for rapid signaling, coordination, and movement, and can undergo transient, rapid changed in their membrane potentials that serve as either electrical signals or stimulators of cellular action
Skeletal - voluntary and striated
Cardiac - striated and involuntary
smooth = involuntary and unstriated
What are the four primary tissues? Function of them? locations?
Epithelial - exchange of materials (sheets and glands)
Connective - connects, supports & anchors body parts (tendons, bones, blood/hemolymph)
Muscular - contraction and force generation (skeletal, cardiac, smooth)
Nervous - initiation and transmission of electrical impulses (brain, spinal cord, epithelial linings)
What is an example of positive feedback?
Labour
Signal from mature fetus --> stretch sensors --> mothers hypothalamus --> pituitary gland --> oxytocin secreted (which enhances contractions makes the uterus contract more starting the cycle over again)
How does transport via channels happen?
The channels are highly selective for passive transport
Gated channels require an input signal which is open and closed by - voltage, ligands, pressure
Leak channels are always open
What are the types of ion movement through channels?
leak channels, and gated channels
gated channels = voltage gated, chemically/ligand gated, mechanically, thermally gated
What is the organization of skeletal muscles?
Whole muscle = an organ
muscle fiber = a cell
myofibril = a specialized intracellular structure
thick and thin filaments = cytoskeletal elements
myosin & actin = proteins
Types of guts? aspects of them? what animal uses each?
Blind ended - temporal variation in digestion and assimilation, limited spatial variation (a cavity) = jellyfish, flatworms
Through put - consistency in conditions & resources, spatial variation in function, digestion before assimilation (a tube) = all other animals
What are the 3 types of neurons? Functions? Location?
Afferent = sensory receptor at periphery to respond to stimulus, it lacks dendrites and presynaptic inputs, located adjacent to the spinal cord in a ganglion, and primarily located in the PNS
Interneurons = integrator neurons, only in the CNS, ~99% of all neurons in mammals, more complex neurons in mammals
Efferent neurons = Primarily located in the PNS but cell body in the CNS
The 4 cells of the central nervous system are?
Astrocytes = most abundant glial cells
oligodendrocytes = provide myelin sheaths to the CNS
Ependymal = Line the internal cavities of the CNS
Microglial = immune defense, resting state, and activated state
How are action potentials generated?
By positive feedback
marked changes in membrane permeability to NA+ and K+, voltage gated channels permit rapid fluxes of these ions down their electrochemical gradient
What is the power stroke? The process?
muscle contraction
Binding = myosin cross bridge binds to actin molecule
Power stroke = cross bridge bends, pulling thin myofilament inward
Detachment = cross bridge detaches at end of power stoke and returns to original conformation
Binding = cross bridge binds to more distal actin molecule; cycle repeats
Common factors that are regulated by homeostasis? (hint 8)
Energy-rich molecules = metabolic fuel, import/export, utilization
O2 & CO2 = aerobic metabolism generates CO2 which must be removed
Waste products = directly ingested or byproducts of metabolisms, export, excretion, detoxification
pH/acidity = impacts on electrical signaling
Osmolytes = electrolytes
Volume and pressure = internal fluid
Temperature = functions optimized/evolves for specific T
social parameters = insects ~ superorganisms, and population densities & castes
What are the three nervous systems of the efferent division? Functions?
Somatic = fibers of the motor neurons that supply the skeletal muscles
Enteric = extensive nerve network in the wall of the digestive tract, mostly controlled by the autonomic system
Autonomic = Fibers innervate smooth muscle, cardiac muscle, glands and other non-motor organs
What are the three characteristics of facilitated diffusion?
Specificity, saturation, competition
What are the two refractory periods? What is their main function?
Absolute refractory period = no restimulation, Na+ gates are not at rest, limits frequency of action potential
Relative refractory period = Restimulation can only occur through a stronger than normal stimulus, K+ gates open
What are the two primary types of contractions? Functions?
Isotonic = muscle tension remains constant as the muscle changes length - used for body movements and moving external objects (concentric ~ muscle shortening) or (eccentric ~ muscle length)
Isometric = the muscle is prevented from shortening, tension develops at constant muscle length
Sensors measure - thermoreceptors
Integrators compare - hypothalamus
Effectors respond - sweat glands & blood vessels
Main differences between sympathetic and parasympathetic
Sympathetic = tone activity, fight or flight response, anticipatory and reset changes
Parasympathetic = tonic activity, rest and digest
Both are usually active at any given time but one dominates
The importance of primary active transport are?
Maintain the Na+ and K+ concentration gradients
Regulate cell volume y regulating intracellular solute concentration
A single motor unit produces a weak contraction
more motor unit = stronger contraction
What are the three different steps in the contraction-relaxation priocess?
Myosin ATPase provide (indirectly) the energy for the power stroke of the cross bridge
ATP binding to myosin permits detachment of the bridge from the actin filament
Ca2+ ATPase pump performs active transport into the sarcoplasmic reticulum during relaxation