Human Physiology Midterm Study Guide
Describe the specific changes for these effector tissue/organs function when the efferent component is activated to restore body temperature (person is too hot) Adrenal medulla - ? Sweat glands - ? Skin arterioles - ? Skeletal muscles - ?
Adrenal medulla - epinephrine (when cold though) Sweat glands - open to release heat through sweat Skin arterioles - dilate to dissipate heat Skeletal muscles - relax
What is this describing? "This travels between the receptor and the integrating center"
Afferent limb
What is this describing? "The component in a feedback system that causes a change to reverse the situation and return the value to the normal range"
Effector
What is this describing? "The output of an integrating center is sent to the last component of the system, whose change in activity constitutes the overall response of the system"
Efferent limb
What is the significance of hemoglobin in the transport of oxygen?
It allows oxygen to bind onto the four spots it has open. It only offloads about 25% normally, however, there is still 75% reserves for whenever we need it
What is the location and role of calcium in neuronal function?
It signals for the vesicles to exocyte out of the cell
What are the main biomolecules that we need to remember (according to Dr. LaGrange)?
Monosaccharides (glucose, fructose, and galactose) and phospholipids
What is osmosis and how is it slightly different from simple diffusion?
Net diffusion of water across a membrane, water wants to go where more solute is because there is less water (solute is taking up volume) Osmosis is just the movement of water, whereas simple diffusion moves molecules across the membrane
What is the definition of inspiration?
Process that causes air to enter the lungs
What is the definition of expiration?
Process that causes air to leave the lungs
Compare the conducting and respiratory zones
The *conducting zone* includes the organs and structures not directly involved in gas exchange (provide passageways for air to travel into and out of the lungs) The *respiratory zone* is where the gas exchange occurs (alveoli)
What is this describing? "A physiological value around which the normal range fluctuates"
Set point
What are the forces that allow simple diffusion, primary active, and secondary active transport to occur?
Simple diffusion - concentration gradient Primary active transport - direct use of ATP Secondary active transport - indirect use of ATP
What is the origin of somatic neurons and how are they stimulated or not?
Somatic neurons originate from the spinal column, and their axons pass directly to skeletal muscle without synapsing (single neuron system) They can either be stimulated by the signal that the body wants to move (voluntary control) or by a reflex arc (due to touching something hot)
What is this describing? "This is "heard" by a specific sensor"
Stimulus
How can the temperature setpoint be "reset" under different physiological conditions?
When you are sick, your body recognizes a higher body temperature as the new, momentary "normal", in order to help fight off the infection. If you take medicine to bring the fever down you actually create more work for your body because your body works to bring your temperature back up to the new "normal". As long as your body stays below 105° you will survive
What is the role of the sodium-potassium ATPase in the resting membrane potential
While leakage channels are allowing free movement, the sodium potassium pump restores the ions to their original location The pump moves three sodium out and two potassium in
Why are spinal and cranial nerves classified as being part of the peripheral nervous system?
While these nerves connect directly to the brain and spinal cord, they branch out into the body, therefore stepping into the peripheral nervous system. Spinal nerves are responsible for transmitting information from the muscles, organs, and glands to the spinal cord Cranial nerves are responsible for the receptors found in the head and neck area. Instead of connecting with the spinal cord, these nerves travel directly to the brain
Summarize the reflex responses when temperatures are above and below the normal setpoint
*Above*: 1) Summer in Texas and you go outside 2) Body senses rising temperature, sends afferents 3) Integration center decides to cool your body down 4) Efferents go to effectors 5) Skin arterioles dilate, skeletal muscle relaxes, sweat glands open *Below*: 1) Snowmaggeden in Texas and you go outside 2) Body senses lowering temperature, sends afferents 3) Integration centers decides to heat your body up 4) Efferents go to effectors 5) Skin arterioles constrict, skeletal muscles start to make you shiver, and your body tells you to put on more layers
What are the similarities and differences between the CNS and the PNS with respect to structure and function?
*CNS*: Brain and spinal cord. A localized collection of neuron cell bodies in the CNS is referred to as a *nucleus*. A bundle of axons, or fibers, found in the CNS is called a *tract*. Your body's processing center. *PNS*: Everything outside of the brain and spinal cord. A cluster of neuron cell bodies is referred to as a *ganglion*. A bundle of axons, or fibers, found in the PNS is called a *nerve*. Relays information between your brain and the rest of your body
How can synaptic transmission be altered by disease and/or drugs?
*Cocaine* blocks the reuptake of dopamine *Strychnine* competes with glycine, an inhibitory neurotransmitter *Tetanus toxin* prevents the release of GABA, affecting skeletal muscles
What are the three major homeostatic control systems (explain them)?
*Feedback systems* - Negative feedback ~ Sense something, send information to brain, then change - Positive feedback ~ Oxytocin during labor *Feedforward systems* - "Anticipatory", works before the challenge even arrives (ex: smelling food starts GI tract) *Resetting of set points*
What is homeostasis and why is it important for normal health?
*Homeostasis*: The ability to maintain a "constant" *internal* environment, this depends on integrated regulation by multiple systems
What is the difference between hyperthermia and temperature?
*Hyperthermia* is an elevated core temperature most often associated with physical activities, and in order to bring this down, the body undergoes negative feedback *Fever* is an elevated core temperature, but it is the momentary., new "normal" for the body therefore the body doesn't try to get rid of it right away. This allows the body to fight off the infection or illness
How can osmosis lead to changes in cell volume?
*Hypertonic*: Water leaves the cell, because there is more solute outside of the cell *Isotonic*: Water internally and externally are equal *Hypotonic*: Water is going into the cell, because there is more solute inside of the cell, therefore less water (high-low)
What are the two major fluid compartments of the cell and where are they located?
*Intracellular fluid* is the system that includes all fluid enclosed by in cells by their plasma membranes *Extracellular fluid* surrounds all cells in the body - Blood (plasma) - Interstitial fluid (surrounds all cells not in the blood)
What is the role of leakage channels, voltage-gated channels, and chemically-gated channels in neurons?
*Leakage*: Contributes to resting membrane potential *Voltage-gated*: Responds to changes in electrical properties of the membrane, when voltage become less negative (towards threshold) the channel begins to allow ions to cross the membrane *Chemically-gated*: Opens because a molecule binds with the gate, allows for the usage of neurotransmitters to open up channels
Compare and contrast negative and positive feedback systems
*Negative feedback* tries to move a stimulus in the opposite direction. If I am too hot, my body temperature is increasing, therefore, my body releases sweat in order to attempt to bring my body heat back down *Positive feedback* tries to keep the stimulus going in the same direction. Sort of like a snowball effect. When a woman is giving labor, the pituitary gland releases oxytocin to keep the effects of the labor going, and for it to build up until the baby is born.
What are the major effects of the sympathetic and parasympathetic systems on cardiac muscle, smooth muscle, and secretory glands?
*Parasympathetic* systems are in charge of rest and digest. This allows for the cardiac muscle, smooth muscle, and secretory glands to perform the daily, involuntary functions *Sympathetic* systems are in charge of fight or flight. If there is a danger near, it dilates your eyeballs, shuts down digestion, and speeds up the heart rate and breathing
What are the two main divisions of the autonomic nervous system and what are the major functions of each system? Also, what are their neurotransmitters, and the length of the preganglionic versus postganglionic axons
*Parasympathetic*: - Major function: > Rest and digest - Neurotransmitters: > Pre-ganglionic = Ach (nicotinic receptor) > Post-ganglionic = Ach (muscarinic receptor) - Length of axons > Pre-ganglionic = Long > Post-ganglionic = Short *Sympathetic*: - Major function: > Fight or flight - Neurotransmitters: > Pre-ganglionic = Ach (nicotinic receptor) > Post-ganglionic = NE (adrenergic receptor) - Length of axons > Pre-ganglionic = Short > Post-ganglionic = Long *DRAW THIS OUT TO HELP VISUALIZE*
What are the similarities and differences between primary active and secondary active transport?
*Primary active* uses the direct use of ATP, and *secondary active* uses an electrochemical gradient across a membrane to drive the process (ATP indirectly required) Also, *primary active* transports one ion from low to high, while secondary active transports one ion from low to high, while transporting another from high to low
What are the structures and functions of the pulmonary and systemic circulations?
*Pulmonary*: - Structures: heart, lungs, arteries, and veins - Functions: drop off carbon dioxide to be expelled, and pick up more oxygen *Systemic*: - Structures: heart, body, arteries, and veins - Functions: pick up CO2 from tissues, and drop off oxygen
What are the four major categories of biomolecules?
1) *Carbohydrates*: monosaccharides (glucose, fructose, and galactose), disaccharides (sucrose, maltose, and lactose), and polysaccharides (glycogen, starch, fiber) 2) *Lipids*: steroids, phospholipids, eicosanoids, and triglycerides 3) *Proteins*: composed of amino acids, major categories: structural, transport, contractile, hormonal, enzymes, antibodies, storage 4) *Nucleotides and nucleic acids*: ATP, ADP, cAMP, RNA, and DNA
What are the steps involved in inspiration?
1) Inspiratory muscles contract 2) Thoracic cavity volume increases 3) Lungs are stretched 4) Intrapulmonary pressure drops 5) Air flows into lungs down pressure gradient until pulmonary pressure is 0
What are the steps involved in expiration?
1) Medulla oblongata stops sending nerve impulses to diaphragm and rib cage 2) Diaphragm and ribcage relax 3) Decreased size of thoracic cavity 4) Elastic lungs recoil 5) Air is pushed out
What are the four pulmonary volumes?
1. Resting tidal volume 2. Expiratory reserve volume 3. Residual volume 4. Inspiratory reserve volume
What is a feedforward response? How does it help maintain homeostasis? What is an example of a feedforward system?
A *feedforward* system anticipates changes in regulated variables such as internal body temperature or energy availability, improves the speed of the body's homeostatic responses, and minimizes fluctuations in the level of the variable being regulated - that is, reduces the amount of deviation from the set point An example of this would be the body getting the GI tract ready to digest before we eat just by us smelling food
Describe the oxygen-hemoglobin dissociation curve and its physiological relevance
A graph that describes the relationship of partial pressure to the binding of oxygen to heme and its subsequent dissociation from heme. It also shows that the lower the partial pressure of oxygen, the fewer oxygen molecules are bound to heme
Label and describe the structure of a neuron
A neuron is going to be composed of dendrites, a cell body, axon hillock, an axon, and a presynaptic membrane
What is surfactant and what is its role in normal respiration?
A substance composed of phospholipids and proteins that reduces the surface tension of the alveoli, it keeps the alveoli from collapsing
What is the relationship of afferent and efferent neurons to the spinal cord (spinal nerves) and brainstem (cranial nerves)?
Afferent neurons carry sensory info from receptors in skin/other organs to the central nervous system - i.e., sensory neurons The cell bodies of the afferent neurons are located outside of the spinal cord Efferent neurons carry motor info from brain to peripheral nervous system - i.e., motor neurons Cell bodies are located in the ventral horn of the spinal cord
What is expiratory reserve volume (ERV) and what is its typical value?
Amount of air in excess of tidal expiration that can be exhaled with maximum effort 1200 mL
What is inspiratory reserve volume (IRV) and what is its typical value?
Amount of air in excess of tidal inspiration that can be initiated with maximum effort 3000 mL
What is tidal volume (TV) and what is its typical value?
Amount of air inhaled or exhaled in one breath 500 mL
What is functional residual capacity (FRC) and what is its typical value?
Amount of air remaining in the lungs after a normal tidal expiration (RV + ERV) 2400 mL
What is residual volume (RV) and what is its typical value?
Amount of air remaining in the lungs after maximum expiration; keeps alveoli inflated between breaths and mixes with fresh air on next inspiration 1200 mL
What is vital capacity (VC) and what is its typical value?
Amount of air that can be exhaled with maximum effort after maximum inspiration (ERV + TV + IRV); used to assess strength of thoracic muscles as well as pulmonary function 4700 mL
What is an action membrane potential, how is it generated, and why is it necessary?
An action potential is an electrical signal that allows transmission to be quick and faithful It is generated when graded potentials reach threshold and it is necessary for communication between systems
What is the effect of carbon dioxide on acid-base status?
As carbon dioxide accumulates in the blood, the pH of the blood decreases (acidity increases)
What is the major driving force for air flow into and out of the lungs?
Atmospheric pressure, air pressure within the alveoli (intra-alveolar pressure), and the pressure within the pleural cavity (intra-pleural pressure)
Compare the volume and composition of the intracellular fluid vs the extracellular fluid
Blood plasma has high concentrations of sodium, chloride, bicarbonate, and protein Interstitial fluid has high concentrations of sodium, chloride, and bicarbonate, but relative lower concentration of protein ICF has elevated amounts of potassium, phosphate, magnesium and protein Overall, IF and Plasma contain high volumes of sodium and chloride, and ICF contains high volumes of potassium and phosphate
What are 5 physiological variables and what are their ranges (including units) for which the body attempts to maintain homeostasis? (there are more than 5 so I am going to list a bunch) Note: I am giving the ranges for what is found in the blood
Ca^2+ = 2.2-2.6 mmol/L PO2 (arterial) = 11-13 kPa PCO2 (arterial) = 4.7-5.9 kPa Cl^- = 97-110 mmol/L Aldosterone = 83-277 pmol/L Glucose = 4-6 mmol/L Triglycerides = <1.8 mmol/L pH = 7.38-7.45
At the neuromuscular junction, acetylcholine released from the somatic neuron binds to receptors on the motor end plate that directly open...?
Chemically gated sodium channels
What is the structure of a cell [plasma] membrane?
Composed primarily of *phospholipids*, cholesterol (makes it fluid), and proteins
What is this describing? "The component in a feedback system that compares the value to the normal range"
Control/integrating center
How can disruption of homeostasis cause illness?
Disease is the disruption of homeostasis If our temperature gets too high and we can't get it back down we would suffer heat stroke Diabetes is another example
What are the two ways oxygen is transported in the blood?
Dissolved in plasma Bound to hemoglobin
What are the three ways that carbon dioxide is transported in the blood?
Dissolved in plasma Bound to proteins such as hemoglobin Carried in the form of bicarbonate ion - Role in acid-base status
Draw a cell (neuron) and illustrate the concentrations for the three major ion in the extra- and intra- cellular fluid compartments
Do this on your own
Draw a diagram that shows the somatic nervous system, parasympathetic nervous system, and the sympathetic nervous system, including the adrenal medulla. Show, at least, neurons, neurotransmitters, receptors, and effector tissues
Do this on your own
Draw a neuron and show the locations in the neuron where resting and action potentials occur
Do this on your own
Draw a somatic neuron and a skeletal muscle, indicating their relationship
Do this on your own
Draw a summary reflex for a person with 1) lower than normal body temperature, 2) fever, and 3) hyperthermia
Do this on your own
Draw and describe an afferent neuron and how it "fits" into the peripheral nervous system, including where it synapses
Do this on your own
Draw and list the partial pressures at the alveoli, various vessels in the pulmonary and systemic circulations, and the tissues
Do this on your own
Draw, in order, the blood flow starting at the right ventricle and ending at the right ventricle
Do this on your own
Draw, list the location of, and describe the function of each component of the chemoreceptor reflex
Do this on your own
Draw the homeostatic reflex pathways involved in the regulation of body temperature and be able to explain the functions of the pathway
Do this on your own (look at slide 15 on homeostasis and body temperature regulation)
Give an example of positive feedback (I am giving an example on the back of this flashcard but there are many examples)
During labor, the child presses on and distends muscle of the cervix, triggering the release of oxytocin, which causes muscles in the uterus to contract, leading to more dilation of the cervix, which triggers more release of oxytocin
Consider this scenario: - Intracellular fluid (ICF) concentration of an ion is 50 mM - Interstitial fluid (ISF) concentration of that same ion is 25 mM - Plasma concentration of that same ion is 25 mM If there is a non-gated ion channel in the plasma membrane for this particular ion, which direction and between which fluid compartments would the ion flow?
From intracellular fluid to interstitial fluid
What is the driving force for (net) osmosis to occur?
Gradient, the water inside and outside of the cell wants to be equal, but where there is more solute (such as salt), there is less water, therefore water moves from high to low The movement of water molecules allows for entropy to be created
Give an example of negative feedback (I am giving an example on the back of this flashcard but there are many examples
If blood glucose becomes elevated, the pancreas secretes insulin. Insulin allows glucose to enter cells, lowering blood sugar. (The hormone insulin acts to reduce further effects by inhibiting hormone production)
What would be the effects on afferent and efferent neurons if the spinal cord was severed at various locations on the brainstem or damaged?
If the spinal cord is severed in the mid or lower back, the person is likely *paraplegic*. This could be due to the inability of the afferent neurons to send sensory information to the brain, or the motor neurons being unable to create a proper synapse with the muscle to promote movement If the spinal cord is severed in higher in the back or in the neck, this could cause *paralysis in the arms and down* as well as difficulty breathing on ones own
What is endocytosis and what is exocytosis?
In endocytosis, substances are brought into the cell in a vesicle. In exocytosis, substances are packaged into vesicles and released from the cell.
What is the concentration of sodium inside and outside of the cell respectively?
Inside: 15 Outside: 150
What is the concentration of potassium inside and outside of the cell respectively?
Inside: 150 Outside: 5
What is the concentration of chloride inside and outside of the cell respectively?
Inside: 8 Outside: 100
What are the functions for these proteins? Integral protein - ? - Channel protein - ? - Receptor protein - ? - Glycoprotein - ? Peripheral protein - ?
Integral protein - a protein that is embedded in the membrane - Channel protein - an integral protein that selectively allows particular materials, such as certain ions, to pass in or out of the cell - Receptor protein - type of recognition protein that can selectively bind a specific molecule outside the cell, and this binding induces a chemical reaction within the cell - Glycoprotein - a protein that has carbohydrate molecules attached, which extend into the extracellular matrix. The attached carbohydrate tags on glycoproteins aid in cell recognition Peripheral protein - typically found on inner or outer surface of the lipid bilayer but can also be attached to the internal or external surface of an integral protein, these proteins typically perform specific functions for the cell
How do cell membranes play an important part in compartmentalization?
Keeps different things separate because everything has its own role
Know the steps to the chemical synapse
Know it
What are the variables that are regulated by the respiratory system
Levels of arterial blood gases (PCO2 around 40 and PO2 around 100)
Explain how a low plasma oxygen, high plasma carbon dioxide and high plasma hydrogen is handled by the chemoreceptor reflex
Low plasma oxygen signals the body to breathe more to increase oxygen uptake High plasma carbon dioxide signals the body to breathe more to expel the carbon dioxide High plasma hydrogen signals the body to breathe more to expel carbon dioxide (more carbon dioxide in the body, more hydrogen in the body)
What is dual innervation? What is sympathetic and/or parasympathetic dominance?
Many effector organs of the autonomic nervous system have dual innervation, meaning that they receive competing inputs from the sympathetic and parasympathetic divisions *Dominance* is described as which system is currently controlling the effector regions? Are you relaxed? Parasympathetic is in control then. Are you running for your life? You can thank your sympathetic nervous system for taking the reins during this time
What is inspiratory capacity (IC) and what is its typical value?
Maximum amount of air that can be inhaled after a normal tidal expiration (TV + IRV) 3500 mL
What is total lung capacity (TLC) and what is its typical value?
Maximum amount of air the lungs can contain (RV + VC) 5900 mL
Describe and list, in order, the parts of the upper respiratory tract
Nose, nasal cavity, mouth, throat (pharynx), and voice box (larynx)
Define the term biomolecules
Organic compounds essential for structure and function
Describe how diffusion of oxygen and carbon dioxide occurs and in which direction at the alveoli vs the tissues
Oxygen coming in from the mouth (100 mmHg),
What are the two different types of passive diffusion?
Passive diffusion and facilitated diffusion *Passive diffusion* allows things such as steroid hormones and triglycerides to pass directly through the cell membrane *Facilitated diffusion* proceeds from higher to lower concentration across a membrane. These use a transporter to move solute (usually with a channel protein) These both qualify as *passive* transport
What are the functions of a cell membrane?
Regulates what enters and leaves the cell and provides protection and support
What are the steps in a homeostatic reflex response pathway?
Remember that *afferent* is going toward the integration center and *efferent* is going away from the integration center
What is this describing? "A component of a feedback system that monitors a physiological value"
Sensor/receptor
What are the differences between the autonomic and somatic nervous system?
The *somatic nervous system* is responsible for our interaction with the environment through the use of our skeletal muscles. Withdrawal reflex occurs in this system. This system is a single neuron system. The *autonomic nervous system* is responsible for involuntary control of the body, usually for the sake of homeostasis. This also includes our parasympathetic and sympathetic systems. This system consists of *2 neurons* (pre- and post-ganglionic) and the lengths are different depending on what system you are in.
What is the arrangement of lipids, proteins, and carbohydrates in the cell membrane?
The cell membrane has many proteins, as well as other lipids (such as cholesterol), that are associated with the phospholipid bilayer. An important feature of the membrane is that it remains fluid; the lipids and proteins in the cell membrane are not rigidly locked in place. In addition to this, carbohydrates are present in very small amounts in cells' structure. For instance, some carbohydrate molecules bind with proteins to produce glycoproteins, and others combine with lipids to produce glycolipids, both of which are found in the membrane that encloses the contents of body cells
What is the relationship between the adrenal medulla and the sympathetic division of the nervous system?
The cells of the adrenal medulla are derived from the same embryonic tissue as sympathetic postganglionic neurons; therefore the medulla is akin to a modified sympathetic ganglion. In response to neural stimulation, the medulla secretes epinephrine into the bloodstream. Epinephrine effects are similar to norepinephrine We know that the post-ganglionic neurotransmitter in the sympathetic nervous system is norepinephrine. This shows that the adrenal medulla helps the sympathetic nervous system by providing more neuro transmitters
For the figure typed below, what would be the effect on this pathway if negative feedback were removed? Substrate←←←←←←←←←↑ ↓ ↑ Inactive intermediate 1 ↑ ↓ ↑ ⊖ Inactive intermediate 2 ↑ ↓ ↑ Active product →→→→→→↑
The concentration of the active product would increase
What are the principal inspiratory respiratory muscles?
The diaphragm and the external intercostal muscles
What is the significance of the thoracic space (volume) in respiration, and how does this space determine airflow?
The elasticity of the lungs, and the surface tension of alveolar fluid (water), wants to pull the lungs in. However, surface tension from the pleural fluid, as well as the pull from the thoracic lung wins over the internal pull. Therefore, the lungs are at -4 mmHg intrapleural pressure. When the thoracic wall opens up due to the diaphragm and intercostals pushing outward, air gets suck toward the negative pressure
Where do autonomic fibers originate and how are they stimulated to excite or not?
The first set (pre-ganglionic) originates in the brainstem or spinal cord, and the second set (post-ganglionic) lies outside the central nervous system in the periphery. Their job as excitatory or inhibitory is decided by the receptor that receives the message
Why is negative feedback the most common mechanism used in maintaining homeostasis?
The idea of homeostasis is to stop any outside influences, and maintain control of the body. Therefore, the very idea of *positive* feedback goes against the principle of homeostasis, because positive feedback has no obvious means of stopping
What are examples of effector tissues?
The muscle, gland, or organ cell capable of responding to a stimulus at the terminal end of an efferent nerve fiber
What is airway resistance and what is its effect on airflow?
The pressure difference between the mouth and the alveoli of the lung, divided by airflow. Multiple factors can influence airway resistance including airflow velocity, the diameter of the airway, and lung volume
What are partial pressures (i.e., what is the concept of partial pressures)?
The pressure of a single type of gas in a mixture of gases. For example, in the atmosphere, oxygen exerts a partial pressure, and nitrogen exerts another partial pressure, independent of the partial pressure of oxygen
What is the role that the respiratory muscles play in expiration?
The process of normal expiration is *passive*. The elasticity of the lung tissue causes the lung to recoil, as the diaphragm and intercostal muscles relax following inspiration
Describe how the structure of a neuron is suited for its function
The structure of a neuron has two processes, a giving *and* a receiving end, it's a whole little package! The whole function of a neuron is to transfer impulses, therefore, when one neuron is the whole package (giving and receiving), you can't get much better than that
Describe and list, in order, the parts of the lower respiratory tract
The windpipe (trachea), the bronchi, bronchioles, and alveoli
How does the ion concentrations across the membrane establish the resting membrane potential?
There are more leakage channels for potassium to leave than for sodium to come in, therefore the RMP remains negative due to the loss of so many positively charged potassium ions
What is meant by the statement that "a negative feedback system brings a changed variable back *toward but not necessarily to* its original set point?
There are physiological parameters outside of the set point that are still considered healthy and safe. For example, the set point for our body temperature is 98.6°, but most of us will sit a bit above or below that. The body might have a hard time getting us all the way back to the optimal *set point* because of the continuous interaction with outside influences When you are sick you will be thrown out of homeostasis and negative feedback solely won't be able to bring you back to the set point, you will need to assist your body
Is this a correct statement, or not? "Sensory nerves transmit information from the central nervous system to the peripheral sensory receptors."
This is *not* a correct statement
Is this a correct statement, or not? "The neurotransmitter that binds to muscarinic receptors is norepinephrine."
This is *not* a correct statement
Is this a correct statement, or not? "The presence of surfactant leads to greater collapse of alveoli."
This is *not* a correct statement
Consider this statement about homeostatic control systems. Is it correct, or not? "It is not always possible for homeostatic control systems to restore every variable a normal range in response to an environmental challenge."
This is a correct statement
What is the significance of carbon dioxide being transported in bicarbonate ion?
This reaction allows for the continued uptake of carbon dioxide into the blood down it's concentration gradient It also results in the production of H+ ions, which helps balance our very fragile pH
What is resting membrane potential and what does this look like across a plasma membrane?
With the ions distributed across the membrane, the difference in change is measured at *-70 mV*, the value is described as the *resting membrane potential*
