module 2+3: definitions Flashcards
Reductionism
look at pieces to understand the whole
Emergence
whole is more than the sum of all its pieces
August krogh models
demands conservation of the underlying structure and function
The August Krogh principle
states that for every biological problem, there’s an organism in which it can be most conveniently studied.
Acclimation
changes in physiology in response to a single environmental factor
Acclimatization
changes in physiology in response to a complex natural environment
Conformers
allow internal conditions to change with external conditions (humans have thermoconformers, osmoconformers, ionoconformers)
Regulators
maintain relatively constant internal conditions regardless of external conditions (humans have thermoregulators, osmoregulators, ionoregulators)
Allostasis
things that change to allow homeostasis. Actively change many systems to maintain constancy.
Source
endothermy (animals that use internal processes to generate heat that allows their body to remain warmer) and ectothermy (rely on external conditions as a way of controlling their body temperature)
Stability
homeothermy (animals that keep their body temperature relatively constant) and poikilothermy (allow their body temperature to vary)
Spatial hemotherm
animals that differ in parts of their body at different temperatures
Temporal hemotherm
animals that have a uniform body temperature but one that differs from one time of the day to another
Adaptation
natural selection favours those variations in a population that increase relative fitness.
Physiology
biological function for anatomy (jack rabbits can alter blood flow to their ears for regulation of heat lost to the environment).
Interstitial fluid
liquid filled spaces between cells in many animals. Link exchange surfaces to body cells.
Endotherms
animals use internal metabolic process as major heat source
Ectotherms
can produce some heat but not enough to elevate temperature
Vasodilation
widening of superficial blood vessels near body surface, result of nerve signals that relax the muscles of the vessel walls.
Vasoconstriction
reduces blood flow and heat transfer by decreasing the diameter of superficial vessels
Countercurrent exchange
transfer of heat or solutes between fluids that are flowing in opposite directions.
Bioenergetics
determines nutritional needs and is related to animal’s size, activity, and environment.
Metabolic rate
sum of all energy used in biochemical reactions over a given time interval.
Basal metabolic rate (BMR)
measured over a comfortable range that requires no generation or shedding of heat above the minimum.
Standard metabolic rate (SMR)
determined at specific temperature because changes in environmental temperature alter body temperature/metabolic rate.
Torpor
physiological state of decreased activity and metabolism, adaptation that enables animals to save energy while avoiding difficult and dangerous conditions.
Hibernation
long-term torpor, adaptation to winter cold and food scarcity.
Immune and Lymphatic systems
unction is body defense (fighting infections and cancer)
Components are; bone marrow, lymph nodes, thymus, spleen, lymph vessels, white blood cells
Excretory
unction is disposal of metabolic wastes, regulation of osmotic balance of blood
Components are; kidneys, ureters, urinary bladder, urethra
Endocrine
function is coordination of body activities (digestion and metabolism) Components are; pituitary, thyroid, pancreas, adrenal, and other hormone-secreting glands
Pseudostratified columnar epithelium
single layered cells form mucous membrane lining portions of the respiratory tract, cilia sweep film of mucous along the surface.
Simple squamous epithelium
single layer of platelike cells, function in the exchange of material by diffusion. Thin and leaky, lines blood vessels and the air sacs of the lungs (diffusion of gas and nutrients is crucial)
Simple columnar epithelium
large, brick-shaped cells are found where secretion and active absorption are important. Lines intestines, secreting digestive juices and absorbing nutrients.
Cuboidal epithelium
dice-shaped cells for secretion making up kidney tubules and many glands including thyroid and salivary.
Connective Tissue
cells scattered through an extracellular matrix, holding many tissues and organs together in place. Fibroblasts (numerous cells in the matrix, secreting fibers proteins) and macrophages (engulf foreign particles and cell debris from phagocytosis).
Loose connective tissue
bind epithelia to tissues and holds organs in place
Fibrous connective tissue
dense with collagenous fibers. Found in tendons (muscle to bone) and ligaments (bone to bone at joints).
Bone
mineralized connective tissue. Osteoblasts are bone forming cells that deposit a matrix of collagen. Ca, Mg, and P ions combine into hard minerals within the matrix. Osteons are repeating cell units consisting of layers of mineralized matrix and are deposited around central canal containing blood vessels and nerves.
Adipose tissue
stores fat in adipose cells distributed throughout the matrix. These tissue pads insulate the body and store fuel as fat molecules. Contains a large fat droplet that swells when fat is stored and shrinks when the body uses fat as fuel.
Cartilage
contains collagenous fibres embedded in a rubbery protein-carb complex called chondroitin sulphate (chondrocyte cells secrete collagen and chondroitin sulphate making strong but flexible material).
Blood
iquid extracellular matrix called plasma, consisting of water, salts, and dissolved proteins. Suspended in plasma are erythrocytes (RBCs), leukocytes (WBCs), and cell fragments (platelets). Red carry oxygen, white function in defense, and platelets aid in blood clotting.
Muscle Tissue
responsible for body movement. Consist of filaments containing the proteins actin and myosin, working together to enable muscles to contract.
Skeletal muscle
attached to bones by tendons, voluntary movements. Consists of bundles of long cells called muscle fibres. arrangement of filaments create a pattern of light and dark bands. Moves bones and body, bundles of long fibres running parallel to the length of the muscle.
Smooth muscle
found in walls of digestive tract, urinary bladder, arteries, and other internal organs. spindle shaped, involuntary body activities (constrict arteries).
Cardiac muscle
contractile wall of the heart, striated. Fibres interconnect via intercalated disks which relay signals from cell to cell and synchronize heart contraction.
Nervous Tissue
receive, processing, and transmission of information (brain information-processing centre). Contains neurons (transmit nerve impulses), and glial cells (support cells).
Neurons: receive nerve impulse from other neurons via cell body and dendrites. Neurons transmit to others (including muscles) via axons, bundled together into nerves.
Glia: nourish, insulate and replenish neurons, modulate neuron function.
Endocrine signalling
secreted molecules diffuse into the bloodstream and trigger response in target cells anywhere in the body.
Paracrine signalling
the secreting cells affects nearby cells
Autocrine signaling
the secreting cell affects itself
Synaptic signalling
neurotransmitters diffuse across synapses and trigger reposes in cells of target tissues (neurons, muscles, or glands)
Neuroendocrine signalling
neurohormones diffuse into the bloodstream and trigger response in target cells anywhere in the body.
Pheromones
chemicals that are released into the external environment, where members of the same species sometimes communicate.
Prostaglandins
modified fatty acids that are produced by many cell types and influence diverse physiological systems (immune response; promote fever and inflammation).
Signal transduction
changes in cellular proteins that convert extracellular chemical signal to a specific intracellular response
Endocrine Tissues and Organs
endocrine cells are grouped in ductless organs called endocrine glands.
Pineal gland: melatonin; regulation of biological rhythms
Hypothalamus
hormones released from posterior pituitary (oxytocin and vasopressin), releasing and inhibiting hormones (regulate anterior pituitary).
Anterior pituitary
follicle-stimulating hormone and luteinizing hormone (stimulate ovaries and testes), thyroid-stimulating hormone (stimulates thyroid gland), adrenocorticotropic hormone (stimulates adrenal cortex), prolactin (stimulates mammary gland cells), and growth hormone (stimulates growth and metabolic functions)
Posterior pituitary
oxytocin (stimulates smooth muscle cell contractions in uterus and mammary glands) and vasopressin/antidiuretic hormone (promotes retention of water by kidneys, influences social behaviour/bonding).
Thyroid gland
hyroid hormone/T3 and T4 (stimulate and maintain metabolic processes) and calcitioning (lowers blood Ca level)
Parathyroid glands
parathyroid hormone (raises blood Ca level)
Adrenal medulla
epinephrine and norepinephrine (raise blood glucose level, increase metabolic activities and constrict certain blood vessels)
Adrenal cortex
glucocorticoids (raise blood glucose level) and mineralocorticoids (promote reabsorption of Na and excretion of K)
Pancreas
insulin (lowers blood glucose level) and glucagon (raises blood glucose level)
Ovaries
estrogens (stimulate uterine lining growth, development and maintence of secondary sex characteristics) and progestins (promote uterine lining growth).
Testes
androgens (support sperm formation, promote development and maintenence of secondary sex characteristics).
Myofibrils
inside fibre, bundles arranged in parallel. Composed of thin and thick filaments (staggered arrays of myosin molecules)
Sarcomere
repeating basic contractile unit of the muscle, borders are lined in adjacent myofibrils.
Z and M lines
thin filaments are attached to Z lines and project toward the centre of sarcomere. Thick filaments are attached at M lines centered in the sarcomere.
Sliding filament model
neither thick nor thin filaments change in length when the sarcomere shortens. Thin and thick filaments slide past each other, increasing their overlap.
Tropomyosin
regulatory protein covers myosin-binding sites along thin filament, preventing actin and myosin from interacting.
Troponin complex
additional regulatory proteins bound to actin strands of thin filaments.
Transverse (T) tubules
infoldings of plasma membrane within muscle fibre allowing action potential spread deep into the interior.
Sarcoplasmic reticulum (SR)
T tubules make contact with this specialized endoplasmic reticulum. Opening CA channels.
Motor unit
consists of single motor neuron and all the muscle fibres it controls
Tetanus
twitches fuse into one smooth sustained contraction when rate is so high the muscle fibre cannot relax at all between stimuli
Myoglobin
oxygen-storing protein
Fast-twitch fibres
develop tension two to three times faster than slow-twitch, enabling brief rapid powerful contractions
Slow-twitch fibres
found in muscles that maintain posture, can sustain long contractions, pumps Ca more slowly.
Intercalated disks
specialized region where the plasma membranes of adjacent cardiac muscles cells interlock at
Hydrostatic skeleton
consists of fluid held under pressure in a closed body compartment.
Peristalsis
movement produced by rhythmic waves of muscle contractions passing from front to back
Exoskeleton
hard encasement deposited on an animal’s surface
Chitin
polysaccharide similar to cellulose, embedded in protein matrix forming material that combines strength and flexibility.
Endoskeleton
hardened internal skeleton, buried within soft tissue.
Ball-and-socket joint
found where humerus contacts shoulder girdle (and femur to pelvic girdle), enabling arms and legs to rotate and move in several planes.
Hinge joint
between humerus and the head of the ulna, restricts movement to a single plane
Pivot joint
enable rotating the forearm at the elbow and turning the head from side to side.
neurons
giant ring axon, receives information from dendrites and the edge of the bell
Cell body
where the neuron’s organelles, including nucleus, are located
Dendrites
highly branched extensions of the neuron, receiving signals from other neurons
Axon
extension that transmits signals to other cells, longer than dendrites. Axon hillock is where signals that travel down the axon are generated.
Synapse
space between end of axon (axon terminal) and target cell.
Neurotransmitters
chemical messengers pass information from transmitting neuron to the receiving cell (presynaptic cell). The neuron, muscle, or gland cell that receives the signal is the postsynaptic cell.
Glial cells
nourish neurons, insulate axons of neurons, and regulate the extracellular fluid surrounding neurons.
Sensory neurons
transmit information about external stimuli such as light, tough, or smell (or internal conditions; blood pressure and muscle tension)
Interneurons
form local circuits connecting neurons in the brain
Motor neurons
transmit signals to muscle cells, causing them to contract
Central nervous system (CNS)
neurons carry out integration
Peripheral nervous system (PNS)
neurons carry information in and out of CNS
Membrane potential
charge difference, voltage, ion gradients and ion channels interact across thin cell membranes and create a source of electrical potential energy.
Resting membrane potential
inactive neuron, not sending a signal. Between -60 and -80 milliVolts.
potassium intracellular and extracellular concentrations
140mM, 5mM
sodium intracellular and extracellular concentrations
15mM, 150mM
chloride intracellular and extracellular concentrations
10mM, 120mM
anions inside cell (proteins) intracellular concentration
100mM
Hyperpolarization
increase in magnitude of the membrane potential, makes inside of membrane more negative (Ek=-90 mV at 37*C)
Depolarization
reduction in the magnitude of the membrane potential, neurons often involve sodium channels (Ena=+62 mV at 37*C)
nersnt potential
Ex= 62mV (log[X]outside/[X]inside)
Action potential
depolarization shifts the membrane potential sufficiently , massive change in membrane voltage
Voltage-gated ion channels
opening or closing when the membrane potential passes a particular level.
Refractory period
a second action potential cannot be initiated
Myelin sheath
electrical insulation that surrounds vertebrate axons
Oligodendrocytes
produce myelin sheaths in CNS
Schwann cells
produce myelin sheaths in PNS
Nodes of ranvier
gaps in myelin sheath, causing voltage-gated sodium channels are restricted
Saltatory conduction
action potential appears to jump along the axon from node to node.
Ligand-gated ion channel
receptor protein that binds to and responds to neurotransmitters (ionotropic receptor).
Excitatory postsynaptic potential (EPSP)
ligand channels permeable to K and Na open, membrane potential depolarizes toward threshold.
Inhibitory postsynaptic potential (IPSP)
ligand channels selectively permeable to K or Cl open, postsynaptic membrane hyperpolarizes.
Temporal summation
EPSPs add together
Spatial summation
EPSPs produced simultaneously by different synapses on same postsynaptic neuron also add together
Glutamate
amino acid, most common neurotransmitter
Gamma-aminobutyric acid (GABA)
neurotransmitter at most inhibitory synapses in the brain
Biogenic amines
neurotransmitters are synthesized from amino acids and include norepinephrine (made from tyrosine, excitatory NT in ANS)
Dopamine and serotonin
dopamine made from tyrosine and serotonin made from tryptophan. Released at many sites and affects sleep, mood, attention, and learning.
Neuropeptides
short chains of amino acids, serve as neurotransmitters that operate via metabotropic receptors.
Endorphins
other neuropeptides that function as natural analgesics, decreasing pain perception.
halifax consciousness scanner (HCS)
developed by dr. Ryan d’arcy. Listens to special sound recordings while HCS records the person’s brain waves.
Nerve net
controls the contraction and expansion of the gastrovascular cavity formed by cnidarians.
Cephalization
evolutionary trend toward clustering of sensory neurons and interneurons at the anterior end of the body, communicating with cells in nerve cords extending to the posterior end.
Ganglia
segmentally arranged clusters of neurons
Ependymal cells
line ventricles of brain and have cilia to promote circulation of the cerebrospinal fluid
Astrocytes
facilitate information transfer and synapses and can release neurotransmitters. Next to active neurons can cause nearby blood vessels to dilate, increasing blood flow, enabling neurons to obtain O2 and glucose quickly. Regulate extracellular concentrations of ions and neurotransmitters.
Oligodendrocytes
myelinate axons increasing conduction speed of action potentials.
Microglia
immune cells that protect against pathogens
Cerebrospinal fluid
formed in the brain by filtration of arterial blood. Circulates slowly through the central canal and ventricles then drains into the veins.
Grey matter
consists of mainly neuron cell bodies, dendrites, unmyelinated axons, and glia.
White matter
consists of bundled axons that have myelin sheaths, giving axons a white appearance
Autonomic nervous system
involuntary (sympathetic, parasympathetic, and enteric)
Sympathetic division
corresponds to arousal and energy generation (flight or flight)
Parasympathetic division
causes opposite responses that promote calming and return to self-maintenance functions (rest and digest)
Enteric division
active in digestive tract, pancreas and gallbladder.
Forebrain
contains olfactory bulb and cerebrum, process olfactory input (smells), regulation of sleep, learning, and complex processing
Midbrain
coordinates routing of sensory input
Hindbrain
forms the cerebellum, controlling involuntary activities (blood circulation and motor activity coordination)
Basal nuclei
deep in white matter, clusters of neurons that serve as centres for planning and learning movement sequences.
Reticular formation
diffuse network of neurons in the core of the brainstem, determines which incoming information reaches the cerebrum
Suprachiasmatic nucleus (SCN)
group of neurons in the hypothalamus, acts as a pacemaker synchronizing the biological clock in cells throughout the body to the natural cycles of day length (coordinates circadian rhythms)
Amygdala
stores emotional memory (part of limbic systems along with; hippocampus, olfactory bulb, hypothalamus, and thalamus)
Positron-emission tomography (PET)
injection of radioactive glucose analogue enables display of metabolic activity
Functional magnetic resonance imaging (fMRI)
brain activity in a region is detected by changes in the local oxygen concentration. Scanning the brain while performing a task correlates tasks with activity in specific brain areas.
Schizophrenia
- affects neuronal pathways that use dopamine as a neurotransmitter (amphetamine “speed” stimulates dopamine release and create same symptoms)
- alters glutamate signaling (angel dust/PCP) blocks glutamate receptors inducing strong symptoms
Amyloid plaques
aggregates of B-amyloid (insoluble peptide cleaved from extracellular membrane protein found in neurons). Secreatases catalyze cleavage causing it to accumulate in plaques outside the neurons, triggering death of surrounding neurons.
Neurofibrillary tangles
made of tau protein, helps assemble and maintain microtubules that transport nutrients along axons. In Alzheimer’s, tau undergoes changes that cause it to bind to itself, resulting in tangles (relates to early-onset).
Statocysts
mechanoreceptors that sense gravity and maintain equilibrium, a layer of ciliated receptor cells surrounds a chamber that contains one or more statoliths (grains of sand or other dense granules)
Essential amino acids
animals need 20 amino acids to make proteins, most have enzymes to synthesize half of these amino acids (diet includes sulfur and organic nitrogen) the other half is obtained from food
Essential fatty acids
animals produce enzymes to synthesize most fatty acids they need, the rest is because they lack the ability to introduce specific types of double bonds.
Vitamins
organic molecules that have diverse functions and are required in the diet in very small amounts. Are classified as water soluble or fat soluble. Required amount ranges from 0.01 to 100 mg per day.
Minerals
inorganic nutrients (iron and sulfur) that are usually required in small amounts of 1 to 2500 mg per day.
Intracellular digestion
hydrolysis of food inside vacuoles
Extracellular digestion
breakdown food in compartments that are continuous outside of animals body
Hepatic portal vein
blood vessel that leads directly to the liver
Chylomicrons
water-soluble globules, transported out of epithelial cell into lacteal (vessel at core of villus)
Single Circulation
blood passes through the heart once in each complete circuit. Blood collects in the arium then enters the ventricle, contraction pumps the blood to arteries.
Double circulation
blood moving between the heart and the rest of the body (systemic circuit) is separated from blood traveling between the heart and respiratory surface (pulmonary circuit)
Pulmocutaneous circuit
animals respire through lungs and skin
circulation steps
- Contraction of the right ventricle pumps blood two lungs via pulmonary arteries
- Blood flows through to the capillary beds in the left and right lungs loading oxygen and unloading carbon dioxide
- Oxygen rich blood returns from lungs via pulmonary veins to left atrium of the heart
- Oxygen rich blood flows into the hearts left ventricle pumping the blood out to body tissues through the systemic circuit
- Blood leaves the ventricle via the aorta, conveying blood to arteries throughout the body.
- Branches lead to capillary beds on the head and arms, the aorta descend into the abdomen supplying oxygen-rich blood to arteries leading to capillary beds in the abdominal organs and legs
- In the capillaries there is a net diffusion of oxygen from the blood to the tissues and of carbon dioxide in the blood
- Capillaries rejoin forming venules which convey blood to the veins
- Oxygen-poor blood from head, neck, and forelimbs are channeled into the large vein, superior vena cava
- The inferior vena cava drains blood from trunk and hind limbs
- The venue empty blood into the right atrium, oxygen-poor blood flows into the right ventricle
systole vs diastole
contraction and relaxation phases of the cardiac cycle (complete sequence of pumping and filling)
Cardiac output
volume of blood each ventricle pumps per minute (two factors determine; rate of contraction and stroke volume)
Rate of contraction
heart rate BPM (72BPM yields a 5L/min cardiac output)
Stroke volume
amount of blood pumped by a ventricle in a single contraction (ave: 70mL)
Atrioventricular valve AV “lub”
anchored by strong fibres between the atrium and ventricle, preventing them from turning inside out, pressure from a contraction closes the valves keeping blood from flowing back into the atria
Semilunar valves “dub”
located at the two exits of the heart (aorta leaves the left ventricle and pulmonary artery leaves the right ventricle), valves are pushed open by the pressure of contraction. When the ventricles relax blood pressure builds up and the aorta closes to prevent backflow.
Heart murmur
blood squirts back through a defective valve producing and abnormal sound
Sinoatrial (SA) node (pacemaker)
cluster of autorhythmic cells located in the wall of the right atrium, where vena cava enters the heart
Electrocardiogram (ECG/EKG)
currents are recorded by electrodes placed on the skin, graph represents the stages in the cardiac cycle
Atrioventricular (AV) node
impulses are delayed 0.1 second before spreading to the heart apex, delay allows the atria to empty completely before the ventricles contract, signals are conducted to apex throughout the ventricular walls by bundle branches/purkinje fibres.
Sickle-cell disease
abnormal form of hemoglobin polymerizes into aggregates, large enough to distort erythrocyte into an elongated curved shape that resembles a sickle
