Biology 213
What are the three chemical families of hormones?
-Polypeptides - Amino acid derivatives -Steriods
How did scientists identify the estradiol receptor? Based on these results, what could the researchers determine about the estradiol receptor? a) Estradiol receptors are found in uterine tissue b) The estradiol receptor is a protein c) There is more than one estradiol receptor d) A & B e) A, B & C
-Researchers introduced labeled hormone molecules into females, then used density gradient centrifugation to separate molecules in target cells by size -The labeled estradiol was concentrated in a narrow band comprised of the labeled hormone bound to its receptor -After purifying the receptor molecule, they found that proteinase enzymes could destroy it. D. A & B
What are modes of locomotion?
-Walking -Swimming -Flying and gliding -Running
What are the issues with an open circulatory system?
-Without discrete, continuous vessels, the flow of hemolymph cannot be directed toward tissues that have a high oxygen demand and CO2 buildup. Crustaceans are an important exception to this rule; they have a network of small vessels that can preferentially send hemolymph to tissues with the highest oxygen demands.
Summarizing action potential:
-all three phases of an action potential occur in about a millisecond (msec). -an action potential occurs because specific ion channels in the plasma membrane open or close in response to changes in voltage. An action potential always has the same three-phase forms, even though the seize of the resting potential, threshold potential, and peak depolarization may vary among species
Estrogens direct development of secondary sex characteristics are:
-in humans and other mammals, the most important estrogen is estradiol -estradiol has a receptor cell in the nucleus of the targeted cell -the receptor is found only in targeted tissue -- the uterus, mammary glands, and hypothalamus
What are disadvantages of the Exoskeleton?
-provides a limited range of movement -the exoskeleton must be shed (molting) in order for the internal parts to grow. This process makes arthropods vulnerable to predators during molting.
What does locomotion enable animals to do?
-seek food -avoid predators -mate -seek shelter
What are thick filaments made of?
-thick filaments are composed of several strands of myosin -myosin has two subunits: a head and a tail
What are the thin filaments made of?
-thin filaments are composed of two coiled chains of the globular protein actin -one end of each thin filament is bound to the z disk, which forms the end of the sarcomere and anchors the filament -the other end is free to interact with the thick filament
LH affects the testicles in two ways:
1) It is required to maintain both the number and size of Leydig cells, testicular cells that produce testosterone. 2) It stimulates the biosynthetic pathways responsible for testosterone synthesis.
What are the five major categories of chemical signals in animals?
1. Autocrine signals 2. paracine signals 3. endocrine signals 4. neural signals 5. neuroendocrine signals
In juvenile amphibians, cells respond to increased levels of T3 in one of three ways:
1. By growing and forming new structures, such as legs 2. They may die, as in cells that form the tadpole's tail 3. They may change structure and function • For example, changes in existing cells cause a tadpole's long intestine, specialized for digesting plant material, to change into an adult's short intestine, specialized for digesting insects and other prey
What are the three types of skeletal systems?
1. Exoskeletons 2. Hydrostatic skeletons 3. Endoskeletons
What are the four steps involved in the photoperiod?
1. Photoreceptors send signals to the hypothalamus 2. The hypothalamus initiates a series of signals that stimulate sex hormone production 3. In some animals, the photoreceptors are located on the retina, which in turn sends signals pineal gland 4. The pineal gland secretes melatonin, which then sends a signal to the hypothalamus
What are the three types of muscle tissues?
1. Smooth 2. Skeletal 3. Cardiac
The plasma membrane is selectively permeable; only certain substances can cross it. Ions can only cross plasma membranes efficiently in one of three ways:
1. along their electrochemical gradient through an ion channel 2. carried via a membrane cotransporter protein or antiporter protein 3. pumped against an electrochemical gradient by a membrane protein that hydrolyzes ATP
What are the three phases of action potential?
1. depolarization 2. repolarization 3. hyperpolarization
Hormones coordinate the activities of cells in three areas, what are these?
1. development growth and reproduction 2. response to environmental challenges 3. maintenance of homeostasis
What are the four functions of the skeletal system?
1. protection from physical and biology intrusion 2. maintenance of body posture 3. Re-extension of shortened muscles 4. Transfer of muscle forces
There are many passive K+ channels and very few Na+ channels. What does make the membrane?
100x more permeable to K+ than to Na+
How much of the atmosphere is made up of oxygen?
21% - but its partial pressure depends on altitude
On average how much air moves into and out of the lungs in an average breath?
450 mL
What is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber? 1. Tropomyosin shifts and unblocks the cross-bridge binding sites. 2. Calcium is released and binds to the troponin complex. 3. Transverse tubules depolarize the sarcoplasmic reticulum. 4. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP. 5. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane.
5, 3, 2, 1, 4
What do membrane potentials typically measure at?
65-80 mV
How much of the oxygen is bound to hemoglobin in blood?
98.5%. The other 1.5% is dissolved in plasma
What does an ion have to use in order to cross the membrane?
A channel that facilitates its movement
In the context of nervous and endocrine systems working together, what is the endocrine systems roll?
A collection of glands and organs that secrete chemical signals. Endocrine communication is slower and more prolonged than electrical communication.
What does this countercurrent exchange system create?
A large partial pressure of oxygen and the carbon dioxide in water over blood. This ensures efficient exchange of gases over the gills
What is the aorta, and its structure function?
A large vessel (artery), generally receives blood from the heart. Has elastic walls, allowing it to expand when blood enters it under high pressure form the heart
What is considered the lung in frogs and other amphibians?
A simple sac lined with blood vessels
What is an exoskeleton?
A skeleton that encloses an animal's body. Arthropods are examples of animals with exoskeletons
Alveoli provide an interface between air and blood that consists of...?
A thin aqueous film. A layer of epithelial cells. Some extracellular matrix material. The wall of a capillary.
What does the action potential depend on?
A voltage-gated channel.
What is movement for?
A way for animals to respond to stimuli from their environment
What does ADH do?
ADH as a peptide hormone regulates water uptake in kidneys, and as a neurotransmitter influences mammalian mating and pair-bonding behavior
What is step 4 of actin and myosin interact?
ADP is released, and the myosin filament is ready for binding to another ATP molecule. As ATP binding, hydrolysis, and release continue, the two ends of the sarcomere are pulled closer together
What is step 1 of actin and myosin interact?
ATP binds to myosin head, causing the conformation change that releases the myosin from the actin
What is step 2 of actin and myosin interact?
ATP hydrolyzed. ATP is hydrolyzed to ADP and inorganic phosphate (Pi), the myosin neck straighten and the head pivots and binds to a new actin subunit farther down the thin filament. The myosin head is now ready for the power stroke
What does acetylcholine do?
Acetylcholine (ACh) is deposited into the synaptic cleft between the motor neuron and the muscle cell. ACh then binds to the receptor on the membrane of the muscle cell.
What are the two types of proteins sarcomere's are made of?
Actin - thin filaments Myosin - thicker filaments
What initiates a muscle contraction and how?
Action potential must be generated from a motor neuron and received at the muscle. The action potential triggers the release of acetylcholine, a neurotransmitter from the motor neuron.
What are the two systems of the PNS?
Afferent division (bring towards) transmits sensory information to the CNS. The neurons monitor conditions inside and outside the CNS Efferent Division (to carry off) carries commands from the CNS to the body. Neurons carry signals that allow for a respone
What are the tiny sacs mammalian lungs are divided into called?
Alveoli, they increase the surface area for gas exchange greatly. Humans have approximately 150 million alveoli per lung.
Na+ channels are more likely to open as a membrane depolarizes, leading to the opening of additional Na+ channels, and further depolarizing the membrane. What does this result in?
An "all-or-none" signal that propagates rapidly without degradation. The ability to send signals over long distances rapidly, without distortion was an important factor allowing evolution of complex physiological behavior.
What is a membrane potential?
An electrical potential difference ALL cells have across their plasma membrane
What is the posterior pituitary?
An extension of hypothalamus. Hormones are produced by neurosecretory cells of the hypothalamus, then stored in the posterior pituitary and released into the bloodstream. This is an example of neuroendocrine pathway.
What is hemoglobin?
An oxygen-carrying molecule
What types of blood vessels are found in the closed circulatory system?
Arteries, capillaries, veins
______ have muscle fibers called _____ wrapped around their circumference.
Arterioles, sphincters. Relax and contract --> moderating flow
What is an autocrine signal?
Autocrine signals act on the same cell that secretes them. An example of this is cytokines - immune responses
Which of the following statements regarding hormones is FALSE? A. Hormones can be steroids, peptides or polypeptides. B. A hormone can bind to multiple receptors on the plasma membrane. C. Several different hormones can impact the same physiological function in an organism D. Hormones are controlled by negative feedback E. Hormones are chemical signals carried through the bloodstream
B. A hormone can bind to multiple receptors on the plasma membrane.
Which of these choices describes the action of steroid hormones? A. steroids bind to receptors on the cell surface B. steroids bind to intracellular receptors C. steroids cause phosphorylation of target proteins D. steroid hormones are produced in large quantities because of their importance to physiology.
B. steroids bind to intracellular receptors
Why doesn't action potentials propagate back up the axon?
Because sodium channels are refractory. Once they have opened and closed, they are less likely to open again for a short period of time. In this way, an action potential is continuously regenerated as it moves down the axon. The signal does not diminish as it moves, because the response is all or none.
The potassium channels involved are sometimes called leak channels. Why are they called this?
Because they allow K+ to leak out of the cell. As K+ moves out of the cell, the inside becomes more negatively charged relative to the outside.
How does the body control homeostasis of blood pressure?
Blood movement is carefully regulated at an array of points throughout the circulatory system. The nervous system can accurately control blood flow to various tissues by contracting or relaxing the arteriolar sphincters. Falling blood pressure is detected by baroreceptors in the walls of the heart and major arteries.
A pattern in blood pressure and blood flow.
Blood pressure drops dramatically as blood moves through the capillaries, because the total cross-sectional area of blood vessels in the circulatory system increases greatly. The drop in blood pressure decreases the rate of blood flow to allow sufficient time for gases, nutrients, and wastes to diffuse between tissues and blood in the capillaries.
Diastolic Blood Pressure
Blood pressure measured just before ventricular ejection
What is hypertension?
Blood pressure that is consistently higher than 140/90 mmHg is high blood pressure. This puts mechanical stress on arteries; if the walls of an artery fail, the individual may experience heart attack, stroke, kidney failure, and burst or dilated blood vessels.
What is bone?
Bone is made up of cells in hard extracellular matrix of calcium phosphate
In what ways does vegetation affect climate?
By altering the ratio of evaporation to precipitation.
How air moved from the trachea into the cells?
By diffusion
How are animal movements triggered?
By electrical signals conducted by nerve cells, or neurons to muscle cells
How is the mammalian rate of breathing established while at rest?
By the medullary respiratory center, an area at the base of the brain. It stimulates the rib and diaphragm muscle to expand and contract.
All of the following are true about skeletal systems except? A. organisms with endoskeletons and exoskeletons have paired flexor-extensor muscles B. hydrostats are characterized by having fluid or tissue under pressure C. Exoskeletons are interior skeletons that support and protect the body D. Endoskeletons contain bones, cartilage and ligaments.
C
What releases the troponin-tropomyosin complex from actin?
Calcium ions binding to the troponin
What are capillaries, and their structure function?
Capillaries are where gases, nutrients, and wastes are exchanged between the blood and other tissues. They are extremely thin. They form an extremely dense network through the body.
what does it look like when the body decrease overall volume when the baroreceptors detect drop in blood pressure?
Cardiac output increases due to an increase in both heart rate and the amount of blood pushed out by the ventricles. Arterioles serving the capillaries of noncritical tissues are constricted to divert blood to more critical organs. The veins are constricted, shifting blood volume toward the heart and arteries to maintain blood pressure and flow to vital organs.
What is cartilage?
Cartilage is made up of cells scattered in a rubbery gelatinous matrix
What are platelets?
Cell fragments that minimize blood loss
What is the endocrine system?
Cells tissues and organs responsible for hormone production and secretion.
What are polypeptides?
Chains of amino acids linked by peptide bonds
What is repolariziation?
Changes the membrane back to a negative charge
What is the structure of a hydrostatic skeleton?
Composed of a body wall surrounded by a fluid, or deformed tissue under compression. Tongues, the penis of humans, and the tubefeet of the starfish are all supported by a hydrostatic skeleton. If the hydrostat is dominated by muscle tissue, it is called a muscular hydrostat.
What is the anterior pituitary?
Connected indirectly to the hypothalamus. Hormones from the hypothalamus travel through blood vessels to the pituitary. In response the pituitary secretes regulatory hormones. This is an example of the neuroendocrine to endocrine pathway
What does the autonomic system?
Controls internal processes. It carries out involuntary responses, which are not under conscious control; smooth muscle, cardiac muscle, and several glands serve as the effectors.
What does the somatic system do?
Controls movement. It carries out voluntary responses, which are under conscious control; skeletal muscles serve as the effectors
In combination, what do electrical and chemical signals allow animals to do?
Coordinate the activities of cells throughout the body.
What is Cushing's disease and how does it happen?
Cushing's is the inability of cortisol to suppress hormone production. This can happen when the feedback mechanism fails, yielding high levels of ACTH in the blood. A constant stress response is a potentially fatal disorder that depletes the body's protein supplies.
The main point of the parabiotic mouse experiment is to show that: A. The hormone must bind to a cell-surface receptor for signaling to be successful B. The hormone must be lipid-soluble for the signaling to be successful C. the hormone must be able to bind to multiple receptors for signaling to be successful D. A hormone and a specific receptor must be present for signaling to be successful
D. A hormone and a specific receptor must be present for signaling to be successful
The movement of charged ions based on concentration gradients when the nerve is at rest... examine the figure to predict the direction Na+ and K+ will move via diffusion based on concentration if all ion channels are open. A. Both Na+ and K+ will move OUT of the cell B. Both Na+ and K+ will move INTO the cell. C. Na+ will move OUT and K+ will move into the cell D. Na+ will move IN and K+ will move OUT of the cell. E. Neither Na+ nor K+ will move across the cell membrane via diffusion
D. Na+ will move IN and K+ will move OUT of the cell.
What three features make the avian ventilatory system efficient?
Dead space in bird lungs is restricted to a short stretch of trachea, between the mouth and anterior air sacs. Birds exchange gases during both inhalation and exhalation. The capillaries in bird lungs cross the parabronchi in a very efficient perpendicular arrangement.
What does it mean the hemoglobin is sensitive to changes in pH and temperature?
Decreases in pH and increases in temperature alter hemoglobin's conformation such that it is more likely to release O2 at all values of PO2. (a conformational change means a change in the shape of the molecule.)
As a result of exercise, the PO2 in muscles tissue _____, the Pco2 _____, and blood pH ____.
Decreases, increases, drops
What is the gas exchange between the environment and cells based on?
Diffusion
What are chemicals that disrupt the action of hormones called?
Endocrine disruptors.
What are the three pathways hormone signaling can take?
Endocrine pathway, neuroendocrine pathway, CNS-to-endocrine pathway.
What is an endocrine signal?
Endocrine signals are hormones and are produced and secreted by specialized cells and discrete organs called glands. Hormones are carried between distant cells by blood and other body fluids
What hormone determines the female sex?
Estradiol - an estrogen, made in the ovaries . Required for further development of the female reproductive tract
What is FSH primary act?
FSH acts primarily on the Sertoli cells, nurse cells that provide support for spermatogenesis.
What are the two major muscle groups with in the endoskeleton?
Flexors and extensors.
What is the seemingly simple events that happen to create complex processes such as moving, seeing, and thinking?
Flows of ions across plasma membranes
Why do animals maximize the surface area available?
For diffusion of gases and other key solutes in a variety of ways: Tiny animals have a small enough volume that diffusion over their body surface is adequate to keep them alive. Tapeworms and flatworms have a high ratio of surface area to volume. They highly folded gastrovascular cavity of jellyfish offers a large surface area for molecular exchange. Diffusion in roundworm is accomplished by a muscular contraction. Large animals require a circulatory system in order to achieve a large ratio of surface area to volume.
____ takes place as CO2 and O2 diffuse between air or water and the blood at the ventilatory surface
Gas exchange
Do respiratory organs provide a lesser or greater surface area for gas exchange?
Greater
How do hormones direct growth and development?
Growth and sex hormones are vital to growth and development in animals an plants. the combination of these hormones promotes cell division, growth, and sexual differentiation.In invertebrates, hormones regulate molting, metamorphosis.
What is an endoskeleton?
Hard structures inside the body
What is the relationship between hemoglobin and heme?
Hemoglobin consists of four polypeptide chains, each of which binds to a nonprotein group called a heme. Each heme contains an iron ion (Fe2+) that can bind to an oxygen molecule. Each hemoglobin molecule can thus bind up to four oxygen molecules.
how is molting triggered?
High juvenile hormone (JH), with surges of ecdysone induce growth of the juvenile by molting.
What does the contraction of the muscle depend on?
How the sarcomeres shorten.
Which surface has the highest albedo? Soil Ice Water Vegetation
Ice
Part C
If tetrodotoxin (TXX) blocks voltage-gated sodium ion channels, which part of the action potential graph would be impacted?
How does the heart work?
In animals with closed circulatory systems, the heart contains at least TWO chambers: The atrium receives the blood returning from circulation. The ventricle generates force to propel the blood through the system
How do ions move across membranes?
In response to concentration gradients as well as charge gradients.
What is a closed circulatory system?
In the closed system, blood flows in a continuous circuit of closed vessels. Pressure provided by the pumping action of the heart. Closed systems are characteristic of vertebrates
Running
In the figure below showing locomotion cost, for an organism with the mass of 100g, which mode of locomotion is the most costly?
What is an open circulatory system?
In the open system, the hemolymph is pumped throughout the body in open vessels: the hemolymph comes in direct contact with body tissues. The open system is characteristic of invertebrates. The hemolymph is pumped by an organ called the heart.
How does electrochemical gradient work?
Ions move along chemical gradient (high to low concentration). Ions move along electrical gradient (move towards opposite charge).
What would happen if the membrane of the membrane potential was removed?
Ions would spontaneously move from the area of like charge to the area of unlike charge -- causing a flow of charge, called an electric current
What happens after CO2 that is produced by cellular respiration enters the blood and RBCs?
It is quickly converted to bicarbonate ions and protons in a reaction catalyzed by the enzyme "carbonic anhydrase"
Why is cooperative binding important?
It makes hemoglobin very sensitive to change in the PO2 of tissues. there for in response to a relatively small change in tissue PO2, there is a relatively large change in the percentage saturation of hemoglobin.
What two hormones have to interact in order for metamorphosis to happen?
Juvenile hormone (JH) and ecdysone. However, JH levels are low, ecdysone triggers metamorphosis and the transition to adulthood and sexual maturity
What are structures of the exoskeleton?
Made up of chitin, the polysaccharide and a protein. Apodemes are the ingrowths where muscles are attached. The apodemes transduce small shortening of the muscles but increase the joint angle. The exoskeleton is jointed with paired flexor and extensor muscles
What does the afferent division do?
Monitor conditions outside and inside the body and respond to light, sound, touch, or other stimuli
Membrane potential changes that produce an action potential part 2
Na+ channels remain less sensitive to depolarizing current for an additional few msec during recovery from inactivation, resulting in the relative refractory period.
Where are voltage-gated sodium ion channels found?
Nerve cells
What are the two basic types of nervous systems?
Nerve net - diffuse arrangement of cells found in cnidarians (jellyfish, hydra, anemones) and ctenophores (comb jellies). Central Nervous System - made up of the brain and spinal cord. Includes large number of neurons aggregated into clusters called ganglia. Most animals with a CNS have a large ganglia or brain, vertebrates
What two systems work together to respond to stimuli in the internal and external environments, thus regulating an animal's internal physiology?
Nervous and Endocrine
What are neural signals?
Neural signals are neurotransmitters that diffuse a short distance from a presynaptic cell to a postsynaptic cell, where it binds to a membrane receptor and results in a change in the membrane potential.
What is the neuroendocrine pathway?
Neuroendocrine signals are released and act directly on the effector cells.
What are neuroendocrine signals?
Neuroendocrine signals are released from neurons but are considered hormones because they are carried by blood or other body fluids and act on distant cells. They do NOT act on or at the synapse. They are often referred to as neurohormones. An example is ADH, antidiuretic hormone, produced by the hypothalamus of the brain but acts on the collecting duct of the kidney, regulating the excretion of water.
What is the CNS to endocrine pathway?
Neuroendocrine signals stimulate cells in the endocrine system, which respond by producing an endocrine signal that acts on effector cells
How do cells communicate?
Neurons are specialized to use changes in membrane potential for fast communication called ACTION POTENTIAL. Neurons have special gated ion channels, that open or close in response to stimuli. Membrane potential may change in response to stimuli that open or close those channels.
Acetylcholine (ACh) is a _____ that binds to _____ receptors on the _____, triggering an action potential.
Neurotransmitter, membrane, muscle cell
Is their a standard structure for gills?
No, gill structure is diverse. Gills can be external or internal.
What does a cardiac cycle consist of?
One complete systole and one complete diastole
What is the path to create movement?
Originates in the CNS, moving to the somatic system of the efferent PNS
What are gills?
Outgrowths of the body surface or throat, used for gas exchange in aquatic animals
How is the overproduction of testosterone prevented?
Overproduction of testosterone is prevented by a negative feedback loop whereby testosterone acts on the hypothalamus and pituitary gland to suppress the release of GnRH as well as LH and FSH, respectively
What does hemoglobin pick up during inhalation for the cycle to begin again?
Oxygen
What is a paracrine signal?
Paracrine signals diffuse locally and act on neighboring target cells. An example of this is fibroblast growth factors - proliferation and differentiation, limb growth)
_____ pressure is the pressure of a particular gas in a mixture of gases
Partial
What kind of channels allow diffusion of K+ and Na+ across the membrane?
Passive
What is the hypothalamic-pituitary axis?
Physical link between the hypothalamus and the pituitary is the root of the connection between the CNS and the endocrine system.
What is step 3 of actin and myosin interact?
Pi released. The PO4 is then released, and the neck bends back to the original position, moving the thin filament relative to the thick filament.
What are the organs that are involved in the Human Endocrine System?
Pituitary gland, thyroid gland, parathyroid gland, kidneys, adrenal glands, pancreas, ovaries/testes
What are the two mechanisms for pumping air?
Positive pressure ventilation - used by frogs. Negative pressure ventilation - used by humans and other mammals.
How are birds able to extract enough oxygen for extremely long flights and flights at high elevations?
Posterior air sacs fill with outside air. Lungs fill with air from posterior sacs. Anterior air sacs fill with air from lungs. Anterior air sacs empty.
What does the sympathetic nervous system do?
Prepares organs for stressful situations -- "fight or flight"
What does the parasympathetic nervous system do?
Promotes relaxation or digestion, functions to conserve and restore energy.
Land vertebrates evolved two separate pumping circuits:
Pulmonary and systemic
Sex hormones play a key role in?
Regulating seasonal reproduction in some species, sperm production, and the menstrual cycle in others.
What does the autonomic nervous system do?
Responds to internal stimuli and controls the activity of internal organs and glands
Maintaining the resting potential is tied to the movement of K+ across the membrane and out of the cell. What does this mean?
Resting neurons are most permeable to K+ ions, which cross the membrane easily along their concentration gradient.
When a neuron is at rest in extracellular fluid, not communicating with other neurons, its membrane has a voltage called the resting potential. what is resting potential?
Resting potential represents energy stored as concentration gradients in a series of ions.
What do the T tubules interact with to allow for muscle contraction?
Smooth Endoplasmic reticulum called sarcoplasmic reticulum. A protein in this ER changes its shape and allows for Ca2+ ions to enter. This allows for the sarcomere to contract
How is the countercurrent exchange system in lamella set up?
So that flow of blood through capillaries is in the opposite direction to the flow of water over the gill surface.
What ions are important in maintaining the membrane potential?
Sodium (Na+), Potassium (K+), and large anions (A-)
What five parameters does Fick's law state for the rate of diffusion of gas depends on?
Solubility of the gas, temperature, surface area for diffusion, differences in partial pressures of the gas across the gas exchange surface, thickness of the barrier in diffusion
How do changes occur in gene expression in target cells?
Steroid hormones are lipid soluble: - can enter a target cell. - bind to receptors inside the cell. - cause a change in gene expression. Steroid-hormone receptor complexes have distinctive DNA-binding region called a zinc finger. how the change in gene expression occurs: Bind directly to the DNA, the steroid hormone receptor complex binds to the hormone-response element for a target gene, then many copies are produced.
What is the key difference between the hormone families?
Steroids are the only hormone that are lipid soluble, meaning it can diffuse through the plasma membrane and bind to receptors inside the cell.
What is an example of paracrine signaling?
Steroids, such as testosterone, are secreted by the testes and stimulate spermatogenesis.
Hormones bind to specific receptor on the surface or inside the target cell. Which of the 5 concepts is this?
Structure function.
What is the most important issue in oxygen availability in water?
Surface area, it has a large impact on the oxygen's ability to diffuse into water
What hormone determines the male sex?
Testosterone - made by the testes, induces development of the male reproductive system and is an androgen
How is the action potential propagated?
The action potential is propagated down the axon: when Na+ enters a cell at the onset of an action potential, positive charges in the cell are repulsed and negative charges are attracted. This results in the charge spreading away from the sodium channels. As positive charges are pushed farther from the intitial sodium channels, they depolarize adjacent portions of the membrane. Nearby voltage-gated Na+ channels pop open in response to depolarization. Positive feedback occurs, and a full-fledged action potential results.
What is the one exception to the lipid-soluble rule?
The amino acid derivative hormone, thyroxine.
When there is an increase in CO2 released into the blood stream what happens?
The co2 reacts with water in the blood and cerebrospinal fluid (CSF) to form carbonic acid, H2CO3, which quickly dissociates into a hydrogen ion, H+, and a bicarbonate ion, HCO3-
What is an electrochemical gradient?
The combination of an electric gradient and a concentration gradient.
What is an endoskeleton composed of?
The connective tissues: cartilage and bone.
What is blood pressure?
The force that blood exerts on the walls of arteries, capillaries, and veins. Blood pressure is given with systolic pressure as the numerator and diastolic pressure as the denominator.
What does carbonic anhydrase catalyze?
The formation of carbonic acid from carbon dioxide in water. Most CO2 is transported in blood (specifically in plasma) in the form of bicarbonate ion, HCO3-
The blood with the highest O2 saturation would come from:
The left ventricle
When a neuron is stimulated, the area of the membrane at the point of stimulation becomes more permeable to Na_. If a cell starts at resting potential (-70mV), and then is stimulated:
The membrane voltage will become >-70mV because the Na+ will move INTO the cell.
Sarcomere filaments slide past one another in a contraction
The model for muscle movement indicates that:
What two distinct nervous systems control organs and glands?
The parasympathetic nervous system and the sympathetic nervous system
How do the muscles take up more oxygen from the blood during exercise?
The partial pressure of oxygen in the blood decreases. At the same time, the muscles release larger amounts of carbon dioxide, increasing its partial pressure in the blood.
What does the oxygen-hemoglobin equilibrium curve or oxygen dissociation curve plot?
The percentage saturation of hemoglobin in RBCs versus the PO2 in blood within tissues. The curve is sigmoida (s-shaped), which is significant due to the binding of each successive oxygen molecule. This represents a conformational change in the protein, which aids in the addition of more oxygen. This phenomenon is called "cooperative binding"
What is depolarization?
The phase which the membrane becomes less negative and moves toward a positive charge
Why is carbonic anhydrase activity in red blood cells important?
The proton produced by the carbonic anhydrase reaction induce the Bohr shift, which makes hemoglobin more likely to release oxygen. the PCO2 in blood drops when CO2 is converted to bicarbonate, maintaining a strong partial-pressure gradient favoring the entry of CO2 into red blood cells
How does the body maintain the resting potential of the sodium-potassium pump?
The pump moves three sodium (Na+) ions out of the cell for every two potassium (K+) ions that it brings in. This helps the cell maintain a separation of charges.
subject 1 sees a picture of jennifer aniston and sees the name printed
The red bars represent action potentials firing when:
How is testosterone produced?
The regulation of testosterone production and release from the testicles involves the hypothalamus as well as the anterior pituitary gland. The hypothalamus produces gonadotropin-releasing hormone (GnRH), a hormone that acts on the anterior pituitary gland to stimulate release of luteinizing hormone (LH) and follicle stimulating hormone (FSH).
What does the release of hydrogen ion do when it dissociates from carbonic acid?
The release of H+ ions lower the blood and CSF pH, which is sensed by specialized neurons, leading to the medullary respiratory center and increasing the breathing rate, which returns the partial pressures of these two gases to resting levels
What do you think that the prediction will be?
The second heart beat will slow
What is the Bohr shift phenomenon?
The shift makes hemoglobin more likely to release oxygen during exercise in which PO2 is high, pH is low, and tissues are under oxygen stress.
What signals the atria to contract simultaneously, then relax?
The sinoatrial (SA) node
If a cat bats a toy, what part of the nervous system is it using?
The somatic system of the efferent division of the PNS
What three conditions does Flick's law state needs to be meet for diffusion in the largest amounts?
The surface area for gas exchange is large, the respiratory surface is extremely thin, and the partial pressure gradient of the gas across the surface is large
In addition to being fast and having three distinct phases, the action potential is an all-or-none event. What does this mean?
There is no such thing as a partial action potential All action potentials for a given neuron are identical in magnitude and duration.
Water has less available oxygen than air.. what does this mean for aquatic animals?
They need to process 30 times more water than the amount of air a terrestrial animal breathes
What does it mean when an endocrine disruptor mimics or partly mimics a naturally occurring hormone?
This can potentially produce overstimulation of hormones such as estrogens (female sex hormone), androgens (the male sex hormone), and thyroid hormones.
When neurological signals cause the breathing rate to increase what happens in the rest of the body?
This increases the rate of oxygen delivery to tissues and muscles. The rate of elimination of carbon dioxide is also increased. The partial pressures of oxygen and carbon dioxide are restored, even during intense exercise
How is the resting potential maintained?
This potential exists in part because neurons have a high intracellular concentration of K+ and low intracellular concentration of Na+ and Cl-. There are also negatively charged proteins inside of the cell.
How do tracheae open to the outside?
Through pores called spiracles.
Where does oxygenated blood enter the heart?
Through the left atrium, which contracts and pushes the blood up into the left ventricle.
How does the human circulatory system return oxygen-depleted blood from the body to the right atrium of the heart?
Through two large veins called the inferior and superior venae cavae
Why is acetylcholine important?
To allow for the action potential spreads into the interior of the fiber through tubules of the cell membrane. The tubules are known as T tubules.
What is one role of epinephrine? How does this happen?
To increase the blood sugar level. Signal transduction occurs when a chemical message at the cell surface triggers a response inside the cell (epinephrine binds to a surface receptor). Epinephrine activates phosphorylase, the enzyme that catalyzes the formation of glucose from glycogen, by triggering a signal transduction cascade. the signal transduction cascade includes a second messenger to amplify the signal.
In the context of nervous and endocrine systems working together, what is the nervous systems roll?
To send electrical impulses rapidly through action potentials that have a short-term effect on a single cell or on a small population of adjacent cells through neurotransmitters.
Why does the left ventricle powerfully contract?
To send oxygenated blood at high pressure through the aorta for systemic circulation system.
In terrestrial animals, air enters the body through the mouth and nose, where it enter the ___?
Trachea
How do trachea open and close in larger insects?
Trachea alternately open and close as the wing muscles around them contract. As a result, the volume of the trachea system changes. As the volume changes, so does the pressure. This means pressure and volume are inversely related. The movement of gases is also aided by larger trachea.
What functions does blood have?
Transport oxygen and carbon dioxide. Transports nutrients to cells from the digestive system. Conveys hormones to target tissues and organs. Delivers cells of the immune system. Distributes heat.
What two proteins block the myosin from binding sites on the actin?
Troponin and tropomyosin.
Which answers below are examples of positive feedback loops? Vegetation feedback Ice-albedo feedback Salt advection feedback
Vegetation feedback Ice-albedo feedback Salt advection feedback
When baroreceptors identify a significant drop in blood pressure, what is a likely response?
Veins constrict, decreasing overall volume
What is the structure function of veins?
Veins have much thinner walls than arteries. But have much larger interior diameters. Larger veins contain valves, thin flaps of tissue that prevent any backflow of blood. Blood pressure in a closed circulatory system is regulated, in part, by active adjustment of the volume of blood in the veins.
_______ occurs when air or water moves through a specialized gas-exchanged organ such as lungs or gills
Ventilation
How do endoskeletons function?
Vertebrate skeletons move by a change in joint angles promoted by the action of antagonistic muscle groups. Muscles exert force only by contracting, so pairs of muscles work together to move a bone back and forth. In all vertebrate animals, the movements of paired muscles are coordinated by motor neurons that originate in the brain or spinal cord. These motor neurons project from processing centers that receive input from sensory systems. Motor neuron activity changes in response to information about balance, smells, sights, and sounds. Thus an animal's movements are directly tied to its sensory systems. The interplay of sensory input and motor output results in coordinated movements.
How is movement of muscles transmitted to the environment?
Via the skeletal system
What are common properties of muscle tissues?
Voluntary vs. Involuntary Multinucleate vs. uninucleate striated vs unstriated
What must flow over the gills in order for the gases to be exchanged?
Water
If water had a higher albedo than ice, how would this alter climate change feedback loops?
Water would reflect more radiation than ice, reducing temperature; this cycle would then be considered a negative feedback loop
What does it mean when an endocrine disruptor binds to a cell?
When an ED binds within a cell, it blocks the endogenous hormone from binding. The normal signal then fails to occur and the body fails to respond properly. Examples are anti-estrogens and anti-androgens
What is the equilibrium potential for K+?
When the membrane reaches a voltage where there is equilibrium between the concentration gradient that moves K+ out and the electrical gradient that moves K+ in. *Even though Cl- and Na+ cross the plasma membrane much less readily than does K+, each type of ion has its own equilibrium potential.
What are steroids?
a family of lipids distinguished by a four ring structure.
A second messenger is needed for epinephrine, what does this mean?
a nonprotein signaling molecule that increases in concentration inside a cell in response to a signaling molecule that binds to the surface.
What are white blood cells (WBCs)?
a part of the immune system
What is action potential?
a rapid, temporary change in a membrane potential.
What do hormones do?
a single hormone can exert a variety of effects
Troponin and tropomyosin can act in unison to ________ the binding of myosin to __________ a) Block, actin b) Enhance, myosin c) Enhance, acetylcholine d) Block, acetylcholine e) None of the above
a) Block, actin
If you wanted to know if the hormone that you recently discovered is an amino acid derivative or a steroid, what would you do? a) Design an experiment to identify where the hormone receptor site is located b) Design an experiment to identify which gland the hormone is secreted from c) Design an experiment to test for neurotransmitter receptivity d) Design an experiment to test for the signaling mechanism (autocrine, paracrine etc.)
a) Design an experiment to identify where the hormone receptor site is located
A decrease in melatonin secretion then sends the signal: a) For the endocrine system to make sex hormones in preparation for reproduction b) For the groundhog to go back into it's hole c) To up-regulate melatonin production d) To suppress the secretion of sex hormones e) For the endocrine system to stop making sex hormones
a) For the endocrine system to make sex hormones in preparation for reproduction
The Key to signal transduction is that: a) The hormone must bind to a cell-surface receptor b) The hormone must be lipid-soluble c) The hormone must be able to bind to multiple receptors d) The second messenger must be already active in the cell e) A beta-receptor must be present
a) The hormone must bind to a cell-surface receptor
How much of the 450 mL actually participates in gas exchange when humans breath?
about 2/3, the other 1/3 of air occupies "dead space" - portions of the air passages, such as the trachea and bronchi, that do not have a respiratory surface.
What is the peripheral nervous system?
all of the components of the nervous system outside the CNS
What proteins does epinephrine bind to?
alpha and beta. there are two types of alpha and two types of beta receptors, therefore, epinephrine has four receptors with four different responses.
What is a tracheae?
an air-filled tube found in insects
A key aspect of hormones that change gene expression is that: a) The hormone must bind to a cell-surface receptor b) The hormone must be able to bind to a receptor that enters the nucleus of the target cell c) The hormone must be able to bind to multiple receptors d) The second messenger must be already active in the cell e) A beta-receptor must be present
b) The hormone must be able to bind to a receptor that enters the nucleus of the target cell
What are tendons?
bands of tough, fibrous connective tissue that attaches bone to muscle
more gill tissue area
based on this data, you might expect tropical fish to have?
What is the study of locomotion in animals called?
biomechanics, measurements of skeletal geometry can reveal information about animal posture, range of motion, and general functions of the skeleton
Troponin and tropomyosin can act in unison to _____ the binding of myosin to ____.
block, actin
How does an endocrine disruptor interfere with natural hormones?
blocking the way natural hormones or their receptors are made or controlled, for example, by altering their metabolism in the liver.
Systolic blood pressure
blood pressure measured in the systemic arterial circulation at the peak of ventricular ejection into the aorta.
The trachea carries inhaled air to narrow tubes called _____.
bronchi
The bronchi branch off into narrower tubes called ___.
bronchioles
How do polypeptides and most amino acid derivatives affect a target cell?
by binding to a receptor on the cell surface.
How is the negative pressure ventilation created in humans?
by the diaphragm
Stimulation of photoreceptors in certain organisms sends signals to the hypothalamus that: a) Increase melatonin secretion b) Lets the organism know that a mate is nearby c) Decrease melatonin secretion d) Suppress the secretion of sex hormones e) Encourages organisms to go into a reduced metabolic state
c) Decrease melatonin secretion
Why is a neuroendocrine signal considered a hormone and not a neurotransmitter? a) It is not considered a hormone b) It is considered a hormone because the origin of the signal is in the hypothalamus c) It is considered a hormone because it acts on distant cells d) It is considered a hormone because it uses autocrine signaling e) It is considered a hormone only when the neurotransmitter receptor binding site has gone through a conformational shift
c) It is considered a hormone because it acts on distant cells
How does the phosphorylation cascade occur?
cAMP binds to an enzyme called cAMP-dependent protein kinase A. This enzyme responds by phosphorylating the enzyme phosphorylase kinase, which then phosphorylates phosphorylase. This chain of events is called a signal transduction cascade.
What are the blood vessels called that run through the lamellae?
capillaries
What is diffused into the alveoli and exhaled from the lungs?
carbon dioxide which is made from the protons from hemoglobin combining with bicarbonate.
Blood is a connective tissue consisting of ...
cells and water.
What processes use intracellular oxygen?
cellular repsiration
In ______ cells use O2 and produce CO2, and O2 and CO2 diffuse between blood and cells
cellular respiration
What are neurotransmitters?
chemical messengers, this is how signals spread
Through ______, dissolved O2 and CO2 are transported throughout the body
circulation
The _____ system is responsible for moving O2, CO2, and other materials around the body.
circulatory
What will happen to ACTH levels if cortisol levels get too high? a) ATCH levels will rise b) Nothing, ATCH is regulated by CRH c) Nothing, cortisol levels impact the hypothalamus d) ATCH levels will fall e) ATCH levels will receive positive feedback
d) ATCH levels will fall
Deoxygenated blood flows from the _______to the _____________. a) Lungs, heart via the pulmonary vein b) Lungs, heart via the pulmonary artery c) Heart, lungs via the pulmonary vein d) Heart, lungs via the pulmonary artery
d) Heart, lungs via the pulmonary artery
Acetylcholine (ACh) is a ___________that binds to __________receptors on the ____________, triggering an action potential. a) Hormone, protein, muscle cell b) Neurotransmitter, protein, nerve cell c) Hormone, membrane, nerve cell d) Neurotransmitter, membrane, muscle cell e) None of the above
d) Neurotransmitter, membrane, muscle cell
Hormones exert their effects in different ways. Thyroid and _______hormones tend to impact ______________, while _________ and amino-acid derived hormones tend to induce ___________. a) Parathyroid; phosphorylation; polypeptide; gene expression b) Steroid; signal transduction cascades; polypeptide; gene expression c) Parathyroid; gene expression; polypeptide; signal transduction cascades d) Steroid; gene expression; polypeptide; signal transduction cascades
d) Steroid; gene expression; polypeptide; signal transduction cascades
Some side effects of taking anabolic steroids are testicular shrinkage and infertility. Why is this? a) The anabolic steroid injections decrease the negative feedback controlling the release of LH and FSH, resulting in less stimulation of the testicles b) Spermatogenesis is halted by the toxic impacts of the anabolic steroids c) The anabolic steroid injections create a positive feedback loop that encourages testosterone production d) The anabolic steroid injections increase the negative feedback controlling the release of LH and FSH, resulting in less stimulation of the testicles
d) The anabolic steroid injections increase the negative feedback controlling the release of LH and FSH, resulting in less stimulation of the testicles
If tetrodotoxin (TXX) blocks voltage-gated sodium ion channels, which part of the action potential graph would be impacted?
depolarization
Ions cross the membrane by: a. primary active transport b. secondary active transport c. passive diffusion d. a & C e. a, b & C
e
Ions cross plasma membrane by: a) Primary active transport b) Secondary active transport (cotransport) c) Passive diffusion d) A & C e) A,B, & C
e) A,B, & C
Why might long term cortisol production have negative effects? a) Degradation of muscle protein causes weakness b) The immune system is suppressed c) Inflammatory responses are repressed d) There is an overall fitness trade-off for inducing longterm stress response e) All of the above
e) All of the above
oxygen and carbon dioxide diffuse between the ___ and ___ along their respective partial-pressure gradients
environment, cells
example of amine hormones:
epinephrine and norepinephrine
Not all glands in the body are part of the endocrine system. What is an exocrine gland?
exocrine glands deliver their secretions through ducts into a space other than the circulatory system.
What are other names of the water portion of blood?
extracellular matrix or plasma
What are ligaments?
fibrous tissues that bind bone to bone
What are the long, thin structures called that extend from each gill arch?
gill filaments
example of a peptide hormone:
growth hormone, insulin, glucagon, cholecystokinin, secretin
what habitats tend to be oxygen poor?
habitats where most organisms live off existing organic material
what habitats tend to be relatively oxygen rich?
habitats with large numbers of photosynthetic organisms
What is an exoskeleton?
hard, hollow structures that envelop the body
Deoxygenated blood flows from the _____ to the _____.
heart, lungs via the pulmonary artery
H+ produced as a result of the disassociation of carbonic acid in RBCs, can bind to hemoglobin, therefore
hemoglobin acts as a buffer
An increase in blood CO2 concentration leads to a decrease in blood pH, resulting in ...?
hemoglobin molecules releasing O2
What takes up most the H+ produced by the dissociation of carbonic acid?
hemoglobin. therefore, hemoglobin acts as a buffer, minimizing changes in pH
Carbon dioxide is _____ in tissues and ____ in the environment
high and low
Oxygen is _____ in the environment and ____ in tissues.
high and low
In both air and water, oxygen and carbon dioxide move from regions of ...
high partial pressure to regions of low partial pressure
What is each gill filament composed of?
hundreds or thousands of gill lamellae (sheetlike structures)
Is the interior of a cell's membrane hydrophobic or hydrophilic?
hydrophobic and repels ion and molecules with charge.
what does the sodium-potassium pump do?
imports K+ ions and exports Na+ ions, resulting in the concentration of K+ ions being higher inside the cell and Na+ being higher outside the cell.
Where is the partial-pressure gradient that favors the diffusion of CO2 from plasma and RBC's to the atmosphere?
in the alveoli
A large difference in partial pressure between gasses will ____ the rate of diffusion.
increase
A large difference in partial pressure between gasses will _____ the rate of diffusion
increase
Are there generally more negative ions on the inside or outside of the plasma membrane?
inside, which gives the membrane potential a negative sign
What are some of the hormones that affect the same aspect of physiology?
insulin, glucagon, and epinephrine all influence glucose levels in the blood
What is a voltage-gated channel?
ion channels that open and close in response to changes in membrane voltage. The shape of a voltage-gated channel changes in response to the charges present at the membrane surface
what is membrane potential?
ions on both sides of the plasma membrane create an electrical potential
Systemic circulation
is a higher-pressure circuit to and from the rest of the body
Pulmonary circulation
is a lower-pressure circuit to and from the lungs
natural selection favors minimizing the cost of locomotion, what does this mean?
it has been hypothesized that animals use an energy-efficient gait at each speed of locomotion.
Gills present an extremely large or small surface area for oxygen to diffuse across an extremely thin epithelium?
large
What is photoperiod?
length of day, which stimulates the release of sex hormones in some mammals, birds and lizards
what are muscle fibers?
long, slender cells that make up the muscle tissue for the vertebrate skeletal and cardiac system
membrane potentials are measured in?
millivolts (mV)
How do hydrostats move?
movement is achieved by: muscles contract, making the segments narrow. This squeezes the internal fluid, increasing the internal pressure. Pressure pushes outward, extending the relaxed longitudinal muscles. The longitudinal muscles contract and the circumferential muscles relax.
What does the circulatory system do?
moves O2, CO2, and other materials around the body
How to calculate the partial pressure of a particular gas
multiply the fractional composition of that gas by the total pressure exerted by the entire mixture (dalton's law)
What two systems work together to produce movement?
muscle and skeletal
What is the charge of a neuron at resting potential?
negative
What type of feedback regulates the hormone pathways?
negative feedback or feedback inhibition, both regulate homeostasis.
What charge does the intracellular carry?
negative relative to the extracellular
how many directions is water movement over gills?
one
Cells must obtain ___ and expel _____ continuously to support ATP production by mitochondria
oxygen, carbon dioxide
_____ required for, and _____ produced by, cellular respiration must be continuously _____ with the _____.
oxygen, carbon dioxide, exchanged, environment
what are the two distinct systems formed by the hypothalamic-pituitary axis?
posterior and anterior pituitaries are each influenced by different populations of neurons in the hypothalamus. both types of hypothalamic neurons are called neuroendocrine cells because they synthesize and release neurohormones.
Vertebrates actively ventilate their lungs by...
pumping air via muscular contractions
ventilation and gas exchange are accomplished by the _____ system.
respiratory system
What type of animals have hydrostatic skeletons?
sea anemones and jellyfish
What is the endocrine pathway?
sends hormones directly from endocrine cells to effector cells. Example: glucose. the stimulus is eating a meal. the endocrine cell is the pancreas sending the endocrine signal called insulin. the effector cell is the body's muscle cells and liver. the response is lower blood glucose
What is the relationship between PNS and CNS?
sensory information from the receptors in the PNS is sent to the CNS, where it is processed. Then a response is transmitted back to appropriate parts of the body through motor neurons
In some animals the gas-exchange surface is the ___, but in most species it is located in a specialized organ like the ____ of tetrapods, and the _____ of insects, or the ____ found in mollusks, arthropods, and fish
skin, lungs, tracheae, gills
what size animals exchange gases by direct diffusion across the body's surface?
small animals, they mostly live in wet environments
What are myofibrils?
small strands within each muscle fiber. they can be stripped or striated. These striped or striated myofibrils are made up of light and dark areas known as sarcomeres. The sarcomere becomes shorter as the myofibril contracts and longer when the sarcomere relaxes
Animal hormones are present in extremely _____ concentrations, yet have ____ effects.
small, large. An example: Growth Hormone (GH). Remove the pituitary gland and the animal stops growing. It was concluded that the GH stimulates mitosis and growth. In dairy cows, there is only 0.04 g of GH per kg of cow pituitary, a very small amount of GH producing a very large animal.
oxygen and carbon dioxide diffuse into water from the atmosphere, but the amount of gas that dissolved depends on several factors. what are they?
solubility of the gas in water, temperature of the water, presence of other solutes, partial pressure of the gas in contact with the water.
Animals with lungs include...
some fish, amphibians, reptiles, birds and mammals
All animals except which have neurons and muscles?
sponges
What do thyroid hormones T3 and T4 do?
stimulate metabolism, promote growth, and increase heart rate
What is the interface between two neurons called?
synapse
what is the space between the dendrite and axon called?
synaptic cleft
Inside the synapse, what does the axon contain that stores neurotransmitters?
synaptic vesicles
example of steroid hormones:
testosterone, estrogen, progesterone, cortisol
Physical link between the hypothalamus and the pituitary is the root of the connection between what?
the CNS and the endocrine system
What is peristalsis?
the alternating relaxation and contraction of the two muscle layers causes a wave known as the peristalic wave.
What signals the ventricles to contract with the atria are relaxed?
the atrioventricular (AV) node. The contraction phase is the systole. the relaxation phase is the diastole
What does the lung enclose?
the bronchioles and portions of the bronchi
Oxygen will move from ____ to ____
the environment, the tissues
oxygen will move from ____ to _____.
the environment, the tissues.
What is the sliding-filament model?
the filaments slide past one another during a contraction
What does multiple sclerosis do to the neuron?
the immune system destroys myelin which effects coordination among neurons
What is the organ for gas exchange in terrestrial animals?
the lung
What is hyperpolarization?
the membrane becomes more negative than it was during the resting potential
Articulations/joints
the place where bones meet and interact. Bones articulate in ways that allow limbs to swivel, hinge, or pivot
what is the postsynaptic neuron?
the receiving cell
what is presynaptic neuron?
the sending cell
What are the two divisions of the efferent division?
the somatic system and the autonomic system
Where does the blood go once the right atrium contracts?
to the right ventricle, which then contracts, sending blood to the lungs via the pulmonary artery
What do Red Blood Cells (RBCs) do?
transport oxygen from the lungs to body tissues, and participate in transporting carbon dioxide from tissues to lungs. In humans, red blood cells make up 99.9% of the formed elements
The calcium ions released into the cytosol during excitation of skeletal muscle bind to ____.
troponin complex
What are the antagonistic muscle groups of the peristalic wave?
two layers of muscles, longitudinal and circumferential. (antagonistic muscles that re-extend to one another through the skeleton)
What is a hydrostatic skeleton?
use the pressure of internal body fluids to support the body
What does the respiratory system do?
ventilation and gas exchange
Who has a closed circulatory system?
vertebrates, and a few other lineages where individuals tend to be active. Such as, annelids, most of which live as active burrowers and hunters, are able to obtain and circulate enough oxygen to support intense muscular activity. A similar situation occurs in squid, octopuses, and other cephalopods that hunt down prey.
In addition, these gases (along with ____, ____, and other types of molecules) must be transported throughout the body
wastes, nutrients
Water is ~1000 times denser than air and flows less easily... what does this mean for aquatic animals?
water breathers have to expend more energy to ventilate their respiratory surfaces than air breathers do
What is signal transduction?
when a message is changed into a form that is active inside of the cell
when a membrane potential exists, do ions on both sides of the membrane have potential energy?
yes
Summarizing the Hormone-Receptor Interaction.
• Although hormones are broadcast throughout the body via the bloodstream, they act only on cells that express the appropriate receptor - Target cells respond to a particular hormone because they contain a receptor for that hormone
Different Target Cells Respond in Different Ways, what does this mean?
• Amplification through a signal transduction cascade explains why tiny amounts of hormones can have such huge effects on an individual • Signal transduction cascades are diverse and complex • The same hormone and receptor can give rise to different responses in different target cells
What is Hormone Disruptors?
• Chemicals that disrupt the action of hormones are termed endocrine disruptors - Many of the disruptors are xenoestrogens - These chemicals bind to estrogen receptors and cause the estrogen-like effects • This affects the physiology or behavior of the animal • Other examples of endocrine disruptors: - The herbicide atrazine can cause reproductive abnormalities among other impacts - Bisphenol (BPA) can cause abnormal development of the brain and reproductive tissue
What are the Leptin and Energy Reserves?
• Parabiosis is the anatomical and physiological union of two organisms. It produced either naturally—as in conjoined twins—or artificially • The following genetic experiment was conducted to prove that obese and diabetic mice were a result of cell-to-cell signaling - In the 1970s, biologists began studying mutations in mouse genes called obese (o) and diabetic (d) - Homozygous obese (ob/ob) and diabetic (db/db) mice eat large quantities of food and move much less than heterozygous or wild-type siblings do • The homozygotes also become extremely obese
leptin and energy reserves experiment
• Researchers performed parabiosis between db/db and ob/ ob mice—both of which are obese—and lean mice, to find out if hormonal signaling that affected appetite was occurring • The results of the experiment were striking - When a db/db animal was joined to either a lean animal or an ob/ob animal, the db/db mouse continued to eat and grow normally; but its partner stopped eating, lost weight, and eventually died of apparent starvation - When ob/ob animals were joined to lean animals, the ob/ ob mice ate less food and gained weight less rapidly than did ob/ob mice joined to other ob/ob mice • Biologists hypothesized that mice produce a satiation, or "stop-eating," hormone—a negative feedback signal in homeostasis with respect to fat stores - The interpretation was that db/db mice lack the receptor required for the hormone to affect target cells • The satiation hormone itself was postulated to be encoded by the obese gene - This hormone, which researchers called leptin, reduces appetite in response to increases in adipose tissue mass - Therefore, ob/ob mice do not produce leptin
