Exam 3 BIO122 Flashcards
Anatomy
The form or shape of a structure is its anatomy.
Physiology
Anatomy allows for particular functions to occur, called physiology.
What are anatomy and physiology shaped through?
Evolutionary forces, most obviously natural selection.
What is anatomy and physiology correlated across?
Hierarchical scales
Examples:
- Shape and distribution of charges gives molecuels their functions.
- Combinations of cells give tissues specific properties.
What allows for the specific functions of animal parts?
The shapes of them
Fish gills
The anatomy of fish gills allows for extremely efficient exchange of gases with the environment due to counter current exchange of blood and water.
Can physics constrain the possible morphology of an organism? If so, how?
Yes.
Cells can only be so small, animals can only be so large, etc.
Most cells must exchange ____ and ____ with the environment and obtain _____ and secrete ____.
O2, CO2, nutrients, waste
What can allow for new functions to evolve?
morphological evolution
What arrangement allows animals to carry out their physical demands with a wide range of morphologies?
Most animals having surfaces dedicated to gas exchange, digestion, and a delivery system to carry gases, nutrients, and wastes between dedicated surfaces and all other cells.
What phenotypic property do animals present that lack a circulatory system?
Thin or flat bodies.
Cnidarians have a thin tissue that surrounds the gastrovascular cavity, such that all cells are close to it.
Do most animal phyla have a circulatory system? If so, what does it do?
Yes.
Allows transport of materials between organs.
Can circulatory systems be “open” or “closed”?
Yes, both arrangements allow for delivery of oxygen, nutrients, homrones, and removal of wastes.
Do most animals regulate some aspects of their biology relative to the external environment? If so, examples?
Yes, regulation of an internal parameter against changes in the external environment is homeostasis.
Temperature, pH, metabolic rate.
How is homeostasis carried out?
Negative feedback loops.
Maintains a constant setting by carrying out actions that counteract the environmental changes away from the set point.
Example: room temperature 20 degrees (set point). —> Room temp increases —> thermostat turns heater off —> room temperature decreases —> room temperature at 20 degrees (set point).
Are many organ systems adapted to carry out homeostasis? Example?
Yes.
Thermoregulation in humans involves sensory neurons in the brain that detect blood temperature, a dedicated center in the brain that acts as a control center, and several mechanisms under the control of the nervous system that can effect body temperature.
What helps regulate body temperatures?
Counter-current exchange mechanisms.
Heat is transferred from warm to cold substances, therefore body parts that stick out in cold environments often have countercurrent blood flow to prevent heat loss to the environment.
What can also effect homeostasis? Examples?
Behavior.
Many animals that can’t thermoregulate will keep their temperature within a certain range by using certain behaviors.
Some that do thermoregulate will use certain behaviors to assist the process.
What are the two dividors of the immune system?
Innate and Adaptive.
Innate: Not specific, found in many animals.
Adaptive: amplified response to a specific threat, unique to vertebrates.
There is overlap between each system.
Which type of cells does the immune system make use of (predominantly)?
Leukocytes or lymphocytes (white blood cells in the blood or lymphatic system).
Lymphatic Vessels
Filter interstitial fluid/blood for pathogens.
Blood circulates throughout the body, and the fluid component leaves capillary beds to bathe tissues (become interstital fluid).
Lymph vessels collect interstital fluid where pathogens can be filtered out by many types of white blood cells.
Lymph nodes, thymus, and the spleen contain large numbers of white blood cells that filter blood for pathogens.
White blood cells also circulate throughout the body in the blood.
Leukocytes and lymphocytes are…
White blood cells.
Innate white blood cell examples:
Mast cells - Involved with inflammation (secrete histamine).
Macrophages and Neutrophils (phagocytes) - Engulf bacteria that aren’t recognized as host cells.
Natural killer cells: Kill host cells that are infected with a virus, or cancerous cells.
Adaptive white blood cell examples:
T cells (helper T cells, cytotoxic, memory)
B cells (activated, memory)
What does it mean when cells become “activated”? Can this happen in both innate and active immune responses?
Divide/mature into several different types of cells.
Yes, happens in both innate and adaptive immune responses.
What do both innate and adaptive responses occur in response to?
A pathogen.
Innate: Rapid, general response.
Adaptive: Slower, specific response.
Innate response:
Rapid general response
- Attack the pathogens external to cells —-> inflamation, phagocytosis –> natural killer cells
-Attack own cells that are infected –> natural killer cells –> inflamation, phagocytosis.
Adaptive Response
Slower, specific response (with memory)
- Attack the pathogens external to cells —–> helper T cells, B cells, antibodies –> cytotoxic T cells
- Attack own cells that are infected (usually with a virus) –> cytotoxic T cells –> helper T cells, B cells, antibodies
Do innate immune defenses include physical barriers?
Yes (anatomy)
Do innate immune defenses include cellular responses? If so, what are they?
Leukocytes - (White blood cells) in the innate immune response include cells that detect pathogens and recruit more cells, cells that can destroy bacteria, and natural killer cells.
Phagocytes - (Macrophages, neutrophils, and others) can engulf bacteria. They recognize bacteria by their cell surface glycoproteins or other markers.
Mast cells - Mast cells and macrophages release modules that can kill bacteria and attract additional leukocytes.
Natural killer cells - Destroy the bodies cells that have been infected with viruses. Virus infected cells typically change their cell markers, whcih the natural killer cells detect. Natural killer cells also destroy cancerous cells using a similar mechanism.
Innate immunity includes an ____ ____.
inflammation response
Histamines
Mast cells release these, they attract other cells and increase blood flow and swelling.
The combination of what two things causes warm swollen tissue that can better fight off pathogens.
Histamines and leukocytes
What is very rapid and sufficient for many infections, but not specific?
Innate immune response.
What allows for “memory” of a pathogen? What is its purpose?
Adaptive immunity.
It does this so the immune system reacts much faster to a pathogen if infected more than once.
Is adaptive immunity and its memory unique to vertebrates?
yes
Adaptive immunity
B cells and/or T cells recognize an antigen.
Antigen binding activates the B/T cells which make clones of itself to amplify the specific antigen recognition.
Antigens are cleared by the adaptive and innate immune responses.
B cells and/or T cells make the memory cells taht recognize the antigen.
What makes the “memory” cells that recognize the antigen?
B cells and/or T cells
Does the secondary immune response include a higher or lower concentration of antibodies than the primary immune response?
higher
How do repeated injections of the same vaccine improve immunity to a pathogen?
a. They increase the copies of B/T cells that originally recognized the pathogen
b. They produce additional memory cells that recognize different antigens on the same pathogen
c. They increase antibodies in the blood that can recognize a pathogen by its antigens
c
What binds to antigens? What does it allow for?
Antibodies. Allows for a large, specific immune response, and memory of the pathogen.
What are pathogens? What are antigens?
Pathogens, such as bacteria, viruses, fungi, and parasites, carry antigens on their surface or within their structure.
Antigens are molecules or molecular structures that are recognized by the immune system as foreign and trigger an immune response.
What recognizes unique molecules (antigens) on pathogens?
Binding sites on antibodies.
What produces antibodies on the surface of a cell?
B cells and T cells
Can antibodies be secreted and circulate in the blood stream?
yes
What do antibodies do?
Bind to pathogens and help direct both the adaptive and innate immune responses to specific pathogens.
What does gene shuffling allow for?
A tremendous diversity of antibodies from a limited number of genes.
What is gene shuffling?
Codons from different genes are mixed and matched to produce unique amino acid sequences in each B cell or T cell as it matures.
How do antibodies fight specific pathogens?
By binding to their antigens which can stick them together.
What engulfs pathogens when antibodies are attached to them?
Phagocytes
What “activates” a cell?
When antibodies on either T or B cells bind an antigen.
What are used as antibody receptors?
B cells and T cells
What can assist in activating B cells (further amplifying the immune response?
Helper T cells
T cell
Cell mediated immunity (attack on infected cells)
B cell
Humoral Immunity (secretion of antibodies by plasma cells)
B cell activation results in…
Antibody production and memory of the pathogen.
What do cytotoxic T cells use antigen recognition to do?
Antigen recognition to identify infected cells and kill them.
Respond to antigens on the surface of infected cells based on their specific antibodies.
Some T cells can become… Some cytotoxic T cells become…
Cytotoxic T cells
memory cells
Cell-mediated immune response (T cell) vs humoral immune response (B cell)
Differences:
T: Cytotoxic T cell, active cytotoxic T cells, memory cytotoxic T cells. (Defend against intracellular pathogens and certain cancers).
B: B cell, plasma cells, memory B cells. (Defend against extracellular pathogens).
Similarities: Antigen-presenting cell, helper T cell, Memory helper T cells
What happens during primary and secondary infection?
Primary Infection: Innate response, slow adaptive response of antibody mediated and/or cell mediated response, formation of memory cells with antibodies to specific pathogen.
Secondary Infection: Innate response, rapid adaptive response due to activation of memory cells.
Osmoregulation
Homeostatic control of water volume and solute concentrations in bodily fluids.
Do different environments challenge the homeostasis of osmoregulatory in different ways? If so, provide an example.
Yes.
Marine invertebrates more or less conform to the osmolality of their environment (regulate via their behavior only).
Terrestrial and freshwater invertebrates osmoregulate.
What is a bizarre mechanism of osmoregulation?
Salt glands allow some marine vertebrates to consume sea water.
Albatross/sea birds, sea turtles, and marine iguanas can survive the consumption of large amounts of sea water due to their ability to secrete excess salt via salt glands.
Do all animals osmoregulate?
No.
Sharks maintain an osmolarity similar to the ocean.
Tardigrades can survive massive changes in osmolarity.
Excretion of wastes is related to ____.
Osmoregulation
What is the majority of osmoregulation of invertabrates carried out by?
By the kidneys, while they filter metabolic wastes from the blood.
Do most animals use a similar or a different waste filtration mechanism?
Similar.
What are the typical steps of waste removal in animals?
- Extracellular fluid is passed into some sort of a tube.
- Valuable components of the fluid are reabsorbed.
- The waste products are concentrated (depending on the animal).
- The waste products are excreted.
Removal of wastes from the body fluid can be ____, and ____.
a. passive, can be regulated
b. passive, can’t be regulated
c. active, can be regulated
d. active, can’t be regulated
e. passive or active, can be regulated
f. passive or active, can’t be regulated
e
How do invertebrates filter wastes?
Using kidney-like organs.
Flatworms have no circulatory system and wastes are excreted into the interstital fluid. Protonephridia collect interstital fluid in flame bulbs.
Annelid worms have a circulatory system which interacts with metanephridium, which is an excretory organ found in many invertebrates.
What do vertebrates use kidneys for?
Filter waste and osmoregulate.
Nephric Tubules
Vertebrates use these, within kidneys to filter wastes from blood plasma.
The outer part of the kidney is the ____ ____, the inner part of the kidney is the ____ ____.
Renal cortex, renal medulla.
What are shorter nephric tubules?
What are longer nephric tubules?
Cortical nephrons
Juxtamedullary nephrons
Different nephrons are used based on the animal’s needs.
How do nephrons filter blood?
Using a combination of passive and active transport mechanisms.
What are the filtration in tissues in kidneys called?
Nephric tubules.
What happens in the Cortex, Outer Medulla, and Inner Medulla (kidneys)
Cortex - (1)Proximal tubule, (4)Distal tubule.
Outer Medulla - (2)Descending limb of loop with Henle, (3)Thick segment of ascending limb.
Inner Medulla - (3)Thin segment of ascending limb, (5)Collecting duct.
Explain the steps of filtration…
- Blood plasma is passed to the proximal tubule. Some salts, nutrients, and water are reabsorbed (removed from the filtrate).
- Filtrate moves down the descending loop of Henle, passively losing water to saltier and saltier conditions.
- Filtrate continues up the ascending loop of Henle. Changes in the tubule pores prevent water movement but allow salt to be removed from the filtrate. Closer towards the cortex salt is actively removed.
- Further modifications are made to the filtrate in the distal tubule.
- The filtrate is passed to the collecting duct, where water and salts are reabsorbed (or not) depending on physiological needs.
What does counter-curret blood flow of the capillaries associated with the nephric tubules allow?
Allows blood to reabsorb salts, water, and nutrients from the kidney interstitial fluid.
What is an effector for osmoregulation?
The collecting duct.
What is the control center for osmotic homeostasis?
The hypothalamus.
Is homeostatic regulation of blood osmolarity via the hypothalamus/ADH an example of a positive feedback loop or a negative feedback loop?
Negative feedback loop
Diabetes
Excess sugar in the urine.
This condition arises when the body either doesn’t produce enough insulin or cannot effectively use the insulin it produces.
The endocrine system consists of…
organs/glands that secrete and produce hormones.
What are hormones?
What do they cause?
Are signaling molecules that travel through the blood.
Cause target cells to change their physiology and/or gene expression.
What do hormones that are used in homeostasis often cause?
Negative feedback loops that arrest hormone secretion.
Hormones (or any signaling molecule) can only effect cells if…
If that cell expresses a receptor to that specific hormone.
Most hormones are ____ ____, and influence cells by…
water soluble, binding to membrane receptors.
Steroid hormones are ____ ____, and travel through…
lipid soluble, blood by binding transport proteins inside of target cells.
Can the same hormone lead to different responses by different target cells?
Yes, cell signaling is context dependent.
How can two different cells respond to the same hormone differently?
Different receptors for the same hormone.
Different signal cascade proteins.
Homeostasis of blood and sugar in diabetes.
Blood glucose concentration is homeostatically maintained.
Insulin signals to target cells (mostly fat and liver cells) to absorb blood glucose and is released from the pancreas when blood glucose is high. (Blood glucose high -> insulin signals)
Glucagon is released from the pancreas when blood glucose is low, including the liver to break down glycogen. (Blood glucose low -> Glucagon)
Diabetes (type 1 vs type 2)
Type I - Insulin is not formed correctly (mutation in the insulin gene), genetic condition.
Type II - Probably environmentally induced (though some might be genetically predisposed to it). Persistent excess blood sugar causes insulin producing cells to die.
What are the brains structures that act as an endocrine organ?
What does this integration allow?
The hypothalamus and pituitary glands.
This integration allows the nervous system and the endocrine system to be integrated.
Where do hormones in the hypothalamus signal to?
Some signal to the anterior pituitary which induces them to release other hormones.
What forms a chain of linked endocrine organs resulting in a hormone signaling cascade?
The hypothalamus and anterior pituitary gland.
What regulates metabolic rate and forms a negative feedback loop with the hypothalamus?
Thyroid hormone
What does insufficient iodine in one’s diet result in?
Incorrectly constructed thyroid hormone.
What determines if a cell will respond to a hormone?
The presence and specificity of a receptor
What is ovulation regulated by in both humans and many other animals?
What hormone do ovaries secrete?
Hormones.
ES and PG
What hormone does the hypothalamus secrete?
What hormone does the anterior pituitary secrete?
GnRH
FSH and LH
Human Ovulation Cycle
- Hypothalamus/anterior pituitary promote follicle maturation in the ovaries.
- Follicle promotes uterine lining and stimulates the hypothalamus.
- Hypothalamus/anterior pituitary induce ovulation.
- Corpus luteum prepares the uterus for pregnancy
What happens hormonally if the egg becomes fertilized?
The embryo produces hCG, which maintains the corpus leteum, which continues to express estrogen and progesterone.
This prevents the breakdown of the uterus (endometrium) and allows for pregnancy.
Human chorionic gonadotropin (hCG) is detectable where…
In the urine of pregnant women.
hCG is produced by embryos to maintain the corpus lutuem and therefore is only present if pregnant.
What are neurons? What are they supported by?
Cells that can conduct electricity.
Glial cells.
The nervous system is made mostly from…
Neurons and glial cells
Neurons receive signals from other neurons via ____, and send signals along ____.
dendrites, axons.
Neurons receive inputs with extensions called…
dendrites
Neurons communicate with other cells by sending an electrical impulse along a projection called an…
axon
What is released from the tips of axons
neurotransmitters
Axon
Conducts signal away from cell body to another neuron or an effector
Axon hillock
Site of origin of axon
Axon terminal
Connects neuron functionally with adjacent neuron or effector
Dendrites
Receive signals and transmit them toward cell body
Cell body
Contains nucleus and most organelles
What does a sodium potassium pump do?
Helps to establish the resting potential of a membrane.
Na+ and K+ gradients are established and maintained by a sodium potassium pump
Why do Na+ K+ pumps require energy (ATP)?
Because they pump ions against their concentration gradients.
Each cycle of the pump consists of what?
3 Na+ are pumped out and 2 K+ are pumped into the cell.
What is resting potential?
What establishes a resting potential?
Difference in charge across the membrane.
The sodium potassium pump combined with some open K+ channels that allow K+ to flow back out of the cell.
Can ions pass through the membranes of neurons without the use of an ion channel?
No
In resting state of a cell, is there more Na+ on the outside or inside of the cell?
Outside
Na+ will diffuse in if allowed.
In resting state of a cell, is there more K+ on the outside or inside of the cell?
Inside
K+ will diffuse out if allowed.
What is resting potential voltage in the typical neuron?
What is the peak voltage of an action potential?
-70mv
40mv
Neurons transmit electrical signals in the form of…
action potentials
Why do action potentials occur?
Voltage gated Na+ and K+ channels
Protein channels that only open at a voltage more positive than resting potential.
When an action potential triggers a Na+ channel to open, this allows some Na+ ions to diffuse into the cell which….
can depolarize the cell (make it more positive).
If a region of the cell becomes depolarized enough, what happens?
The cell will cross threshold here all of the voltage gated Na+ channels in the immediate area will open.
Once this happens, lots of Na+ will diffuse into the cell.
The sudden influx of + ions increases the voltage inside the cell causing it to spike rapidly.
Voltage gated K+ channels open after a slight delay once threshold is reached. This allows…
K+ to diffuse out of the cell, dropping the voltage down again as positive ions rapidly leave the cell.
How does the cell momentarily get polarized (undershooting normal resting potential)? This is called the ____ ____.
Enough K+ ions leave the cell.
refractory period
The refractory period (undershoot) allows for…
only a 1 way propagation of an action potential.
Action potentials move from the ____ ____, down the ____, and do not return.
Why is this possible?
cell body, axon
This is possible because Na+ channels close and cannot be opened again for a few milliseconds after opening. if this was not a thing, there’d be a chance an action potential could backfire.
Why are action potentials considered “all or none”?
Because they are self-propagating and are the same every time.
There are no “kinds” of action potentials.
An action potential either will occur or not, and there are no grades of action potentials.
What is the intensity of a stimulus coded by?
Action potential frequency.
More intense = higher frequency
How are action potentials communicated to the dendrites of other neurons?
Neurotransmitters that diffuse across the synaptic cleft.
Neurotransmitters bind onto ligand gated ion channels.
Pre-synaptic vs post-synaptic neuron
Pre-synaptic - A cell that sends an action potential.
Post-synaptic - A cell that receives an action potential.
Can neurotransmitters both excite and inhibit post synaptic neurons?
yes
Glutamate
Most common excitatory neurotransmitter in the central nervous system. It binds receptors that allow Na+ into the post synaptic neuron.
GABA
Most common inhibitory neurotransmitter in the central nervous system. It binds receptors that allow Cl- into the post synaptic neuron.
Where are the synapses received summed/integrated?
Axon hillock
Neurotransmitters either ____ or ____ neurons.
excite, inhibit
The sum of synaptic inputs can trigger…
all or nothing action potential at the axon hillock.
Neurotransmitters are released from the axon terminal due to what…
action potentials
