Bio Midterm 2 Flashcards
What are the components of the Central Nervous System?
The brain and the spinal cord
What are the components of the Peripheral Nervous System?
- Afferent (input –> CNS) and Efferent (CNS –> body)
- Efferent is split into the somatic nervous system which controls skeletal muscle mobility, and the autonomic nervous system
- The ANS further splits into the sympathetic nervous system and the parasympathetic nervous system
What are the steps of the nervous reflex arc?
- Pain receptor is activated and stimulus occurs (touch hot surface)
- Afferent neuron sends signals to spinal cord
- Interneurons in the spinal cord integrate the information
- One efferent neuron stimulates the flexor muscle to contract (excitatory)
- The other stops the extensor muscle from contracting (inhibitory)
- A reaction occurs, removing body from stimulus
What are chemoreceptors?
- Sensory receptors that detect chemical stimuli such as pH levels, O2 and CO2 levels. Involved in smell and taste
What are mechanoreceptors?
Sensory receptors that sense some form of physical distortion such as an increase in pressure, the bending of a hair follicle, stretching of the lung or movement of a muscle.
What are photoreceptors?
Sensory receptors that sense light (photons)
Describe the signal pathways that occur when a sensory receptor recognises a stimulus
- Stimulus (chemical, light or pressure) is sensed by a receptor protein
- Signal opens or closes an ion channel
- A change in the membrane potential occurs (usually becomes +)
- timulation of the afferent nerve that innervates the sensory receptor cell and the initiation of a nerve signal that is then sent to the central nervous system
What is the process of a signal traveling through a neuron?
- A pre-synaptic cell innervates a post-synaptic cell by passing on a signal to the dendrite
- Stimulation leads to small changes in the membrane potential within the dendrites
- The signal passes through the axon hillock which creates an action potential (AP)
- The AP travels down the axon, hopping between the gaps of the myelin sheath, called the nodes of ranvier
- The AP reaches axon terminals with the synapses which become activated and release neurotransmitters which then transfer the signal to the next post-synaptic nerves’ dendrite(s)
A _____ is a collection of axons from many different neurons. The cell bodies of all of these neurons are found together in ____ or _____.
nerve, ganglia, nuclei
Identify the labeled parts of this neuron diagram
A - Nucleus
B - Soma
C - Dendrites
D - Axon
E - Myelin Sheath
F - Synapse
G - Axon Hillock
H - Axon Terminal
I - Node(s) of Ranvier
_____ functions to remove waste products. ______ help to keep neurons in place and also form the ______-_____ _______
Microglia, Astrocytes, blood-brain barrier
________ (within the central nervous system) and _____ _____(within the peripheral nervous system) form myelin.
Oligodendrocytes, Schwann cells
Nodes of ranvier allowsfor very rapid conduction of nerve impulses by a process called _____ ______
saltatory conduction
Describe the four phases of an action potential
- Resting potential, has a membrane potential usually in the range of -80 to -60 millivolts
- Threshold is reached, Na+ inactivation gates all open, K+ activation gates all closed
- Depolarization, slow increase in membrane potential due to Na+ rapidly moving into the cell through the Na+ channels that have their activation gates open, K+ activation gates begin to close, Na+ inactivation channels begin to close
- Repolarization, peak of the action potential is reached, all Na+ channel inactivation gates are closed and all K+ channel activation gates are open. K+ leaves the cell. Na+ activation gates are all open, but no movement of Na+
5.. Refractory period, Na+ activation gates close, inactivation gates open. K+ inactivation gates open, activation close. K+/Na+ ATPase pump removes excess Na+ and adds K+ to return to resting potential
What does Na+ have to pass through to get from the extracellular fluid into the nerve?
Activation gate: closed when the membrane potential is at the resting level, some open during resting –> threshold phase, all are open threshold –> resting phase.
Inactivation gate: is open at the resting membrane potential, begins to close near peak depolarisation, slowly reopens during repolarisation
What does K+ have to pass through to get from the extracellular fluid into the nerve?
Activation gate: Closed at resting, opens slowly during depolarisation. Closes slowly after peak.
Note: When Na+ inactivation gate is open, K+ activation gate is closed
Once a neuron has generated an action potential there is a period during the depolarisation phase and during the initial stages of the repolarisation phase in which no amount of stimulation can cause this neuron to generate a second action potential. This is called the _____ _____ ______
absolute refractory period
What is the period in which a second stimulus may be able to generate another action potential before membrane potential has returned to the resting level?
Relative refractory period
What’re the two types of synaptic transmission?
Electric synapses: Direct electrical connections between the two cells such that electrical current (i.e., the positive charge carried by Na+ entering the cell) can move directly from one cell into another. Current moves through channels called gap junctions that connect the pre-synaptic cell to the post-synaptic cell.
Neurotransmitters: Enter the space between the two cells (called the synaptic cleft) and they bind to neurotransmitter receptors on the cell membrane of the post-synaptic cell. Generates an AP. Called chemical synapse.
In the case of an ______ neurotransmitter, ion channels of the post-synaptic nerve open and positive ions (like Na+) enter and ______ the cell
excitatory, depolarise
In the case of an ______ neurotransmitter, ion channels on the post-synaptic cell that allow negative ions (such as Cl-) to enter the cell and cause the membrane to _____
inhibitory, hyperpolarize
What does the pineal gland produce?
Melatonin
What does the hypothalamus do?
Activates or inhibits hormones, produces:
- ADH ( + kidney water absorbtion, - urine production)
- Oxytocin (milk production, uterine contraction)
What does the posterior pituitary gland do?
Stores and releases ADH and oxytocin
What does the anterior pituitary gland do?
Produces :
- TSH, + rate of metabolism
- ACTH, helps body cope w stress, regulates fluid levels
- GONADotrophins, produce gametes and hormones in testes and ovaries (human gonads)
- Growth hormone, guess
- ProLACTIN, stimulates milk production (lactose)
- Endorphins, limit pain perception
What does the thyroid gland do?
Produces thyroid hormones (T3, T4), used to controls your body’s metabolism
What does the parathyroid gland do?
Produces parathyroid hormone, used to maintain the right balance of calcium in the bloodstream and in tissues
What does the adrenal cortex do?
Produces:
- Steriods (growth, development, energy metabolism, homeostasis and reproduction)
- Aldosterone (regulates blood pressure by managing Na and K levels in blood)
What does the adrenal medulla do?
Produces catecholamines:
- Dopamine
- Epinephrine (adrenaline)
- Norepinephrine
What hormones does the pancreas produce?
- Insulin: Allows glucose to enter the body’s cells to provide energy
- Glucagon: Stimulating the liver to break down glycogen to be released into the blood as glucose. Activating gluconeogenesis, the conversion of amino acids into glucose. Breaking down stored fat (triglycerides) into fatty acids for use as fuel by cells
What hormones do the ovaries produce?
- Estrogen: Regulates the growth, development, and physiology of the human reproductive system
- Progestins: Help other hormones start and stop the menstrual cycle
Describe circulating hormones and their function
- Synthesised within and released from endocrine cells
- Diffuse through the extracellular fluid, enter the blood and are transported to target tissues
- Bind to receptors on either the target cell’s plasma membrane or within the target cell
- Trigger a physiological response such as the opening or closing of an ion channel
- Circulate in the blood and then act on target tissues by binding to adrenergic receptors which can be subdivided into alpha (α) and beta (β) subtypes.
________ are very similar to circulating hormones. The only difference is that they are synthesised within and released from neurons rather than from an endocrine gland
Neurohormones
In _____ _______, a hormone is released from an endocrine cell (in an endocrine gland or from a neuron) and then acts on the same cell (or same cell type) that synthesised and released it. In _____ ________, a hormone is released from an endocrine cell and diffuses through the extracellular fluid to its target cell. It doesn’t enter, or travel through, the blood.
autocrine signaling, paracrine signaling
Note: In both autocrine and paracrine signaling, the hormones still exert their effects by acting on receptors (on or within the cell).
______ hormones are tyrosine-based. The ______ are an example
Amine, catecholamines
When required, the kidney produces an enzyme called _____ which converts _______ into angiotensin I (in the blood). When blood flows through small capillaries in the lungs, _____ ______ ______ (ACE) which is present in the lung converts angiotensin I into angiotensin II.
renin, angiotensinogen, angiotensin converting enzyme
What are angiotensis I and II examples of and what is their function?
They are examples of peptide hormones
They have effects on blood pressure and blood ion regulation although angiotensin II is more potent than angiotensin I
Describe steroid hormones
- They are lipophilic (lipid soluable; hydrophobic)
- Synthesised from cholesterol
Describe the process that when a hormone binds to a receptor
- Hormone enters blood
- Hormone binds to receptor
- Signal transduction occurs
4a. Cytoplasmic response occurs (ion channels open)
4b. Nuclear response occurs (alters transcription)
What happens during the signal transduction phase of hormone activation?
Either:
- Phosphorilation, a phosphate group is added to a protein or enzyme by protein kinase
or
- Dephosphorilation, a phosphate group is removed from a protein or enzyme by protein phosphatase
Describe the ADH and oxytocin pathway
- Synthesised in the hypothalamus
- Travel down axon from hypothalamus to the terminals in the posterior pituitary where they are stored
- Released into blood when needed
Describe the synthesis and release of inhibitory hormones (IH) and releasing hormones (RH)
- Synthesised in the hypothalamus
- Released into a capillary bed within the hypothalamus
- Blood flows from these capillaries into hypothalamic portal vein (a blood vessel)
- Once the RH and IH are in the capillary bed within the anterior pituitary, they either stimulate (RH) or inhibit (IH) the release of neurohormones that are being produced within the anterior pituitary.
Note: Together the two capillary beds and the blood vessel comprise the hypothalamic-pituitary portal system
The _____-_____-____ axis refers to the regulation of thyroid function by neurohormones that originate from the hypothalamus and the pituitary gland.
hypothalamic-pituitary-thyroid
Describe the process of hypothalamus –> T3 and T4
- The hypothalamus produces thyroid releasing hormone (TRH)
- TRH stimulates the release of thyroid stimulating hormone (TSH)
- TSH stimulates the thyroid gland to produce two hormones, T3 and T4
- T3 and T4 stimulate metabolism and regulate development
What is calcitonin and what is it’s antithesis hormone (hormone with opposite function)?
- Produced by the thyroid gland and is released into the blood when blood calcium levels are too HIGH
- Parathyroid hormone (PTH) is the antithesis hormone as it is released into blood when calcium levels are too LOW
How do calcitonin and PTH regulate blood calcium levels?
- They can cause the deposition or release of calcium from bone (via integration or extraction of Ca2+ from bones).
- They can cause the kidneys to reduce or increase their uptake of calcium (i.e., regulate the amount of calcium lost in the urine).
- Parathyroid hormone can also cause the uptake of calcium from the intestine.
The ____-____-____ axis refers to the regulation of adrenal gland (adrenal cortex) function by neurohormones that originate from the hypothalamus and the pituitary gland.
hypothalamic-pituitary-adrenal
The ____ cells that produce insulin and the ____ cells that produce glucagon are found grouped together in cell clusters called ____ of _____
beta, alpha, Islets of Langerhans
Describe how blood-glucose levels are regulated
- When too high:
Beta cells in the pancreas release insulin into the blood. Insulin triggers cells to take up glucose. Within the liver, insulin also stimulates the production of glycogen - When too low:
Alpha cells in the pancreas release glucagon. Glucagon triggers the liver to breakdown glycogen into glucose molecules and triggers the release of this glucose into the blood
Type ___ diabetes (insulin-dependent diabetes) results from a failure of the pancreatic beta cells to produce enough insulin.
Type ___ diabetes (insulin-independent diabetes) is a result of cells becoming resistant to the effects of insulin. This results from a failure in the signal transduction pathway between the interaction of insulin with its receptor and the activation of glucose transporters on the cell membrane
I, II
What’re some notable long-term effects of diabetes?
- Atherosclerosis (a narrowing of the blood vessels), - Gangrene (tissue necrosis/death)
- Blindness
The ______ ______ is the synaptic connection between a motor nerve and a skeletal muscle. Nerves that regulate skeletal muscle function are called ____ _____.
neuromuscular junction, motor nerves
Describe acetylcholine (Ach)
- When AP reaches axon, Ach is released
- Achs are realeased from pre-synaptic axon, bind to nicotinic receptors in post-synaptic dendrites
- The receptor is a Na+ channel and the binding of Ach to the receptor opens the channel and Na+ enters the muscle cells
- Muscle cell becomes depolarise, an AP is triggered
What are all the components of fascicles, from smallest to largest
- Actin (thin) and myosin (thick)
- Myofibril
- Muscle cells (fibres)
- Fascicle
The plasma membrane of a skeletal muscle cell is called the _____
Sarcolemma
Describe the pathway an AP takes the cause muscle contraction
- Action potential arrives at axon terminal
- Depolarisation of the sarcolemma causes an AP to be triggered in the muscle cell
- AP spreads into the muscle cell via T-tubules
- AP causes release of Ca2+ from the sarcoplasmic reticulum
- Ca2+ is used to contract muscle (somehow?)
If you look at the myofibrils from a longitudinal perspective, you see a repeating arrangement of the thick and thin filaments. Each of these repeating units is called a ______
sarcomere
What is the thin filament?
- Made by two layers of actin which form a double helix, each having a binding site for myosin
When the thick and thin filaments are not sliding across one another, a long regulatory protein called _______ covers all of the myosin-binding sites on the actin molecules
tropomyosin
How does troponin work?
- Protein that binds with released Ca2+ which will cause tropomyosin to change and move away from myosin binding sites
- This allows actin and myosin to bind and slide against eachother (muscle contraction)
What is the thick filament?
- Made up of two intertwined myosin subunits
- Have heads on each end which contain an actin and ATPase binding site
- Have one tail in the middle which connects both heads
- The heads can either be in a high-energy state (before sliding) or low-energy (after one round of sliding)
To facilitate binding of the thick and thin filaments, actin has a myosin-binding site and myosin has an actin-binding site. When the two filaments bind together the site of interaction is called a ________.
crossbridge
Don’t even feel like making this a question. This is an agredious amount of info to remember. But yea just know this cycle of how actin and myosin unbind
The binding of actin to myosin with the myosin head in the low energy configuration is called what?
rigor
Note: This means that the muscles cannot move. Think to rigor mortis which is a posthumous statue like state
What is the difference between isotonic and isometric muscle contractions?
- Isometric = muscle does not “change length”
- Isotonic:
- Concentric: Muscle shortens (flexes)
- Eccentric: Muscle lengthens (extends)
There are proteins that connect the thick filaments together (_____ ______ ______) and proteins that run the length of the thin filaments (_____ _____ _____)
series elastic components, parallel elastic components
When a second AP arrives, if it superimposes the previous tension it is called _____, if the tension plateaus it is called_______.
summation, tetanus
What are the benefits of open or closed circulatory systems?
Open:
- Can allocate blood to specific organs increasing or decreasing the flow
Closed:
- Have a higher pressure which allows for high levels of oxygen supply
What is haemolymph?
The fluid (composed of extracellular fluid and blood) that flows in open systems
What is the pathway of deoxygenated blood –> lungs
- Blood enters heart from the superior and inferior vena cava
- Blood in right atrium flows into right ventricle
- Contraction of right ventricle opens pulmonary valve
- Blood flows through semilunar valve into pulmonary trunk
- Blood is distributed by pulmonary arteries to lungs, CO2 is replaced by O2
What is the pathway of lungs –> oxygenated blood
- Blood returns to heart from lungs via pulmonary veins to left atrium
- Blood flows through left atrioventricular (AV) valve into left ventricle
- Ventricle contracts which opens aortic semilunar valve
- Blood flows through aortic valve into ascending aorta
- Blood flows and distributes O2 to all organs, receives CO2
How do mammalian babies recieve blood when they’re foetuses?
from the placenta, blood flows, via the umbilical vein, into the right atria of the foetus
How does blood shunting work?
- Blood from right atrium is shunted through the foramen ovale (hole in heart), avoids being sent to lungs
- any blood that didn’t get shunted from the right atria to left atria gets shunted through the ductus arteriosus (hole between the pulmonary artery and the aorta)
How do cephalopod (octopi and squid) circulatory systems work?
Bonus points if you can tell me why the fuck I need to know this
- Deoxygenated blood is carried through the gills via two brachial hearts (equiv. to the right side of human heart)
- The now oxygenated blood flows to the systemic heart (equiv. to the left side of human heart) which pumps the blood to the systemic tissues
Bonus answer: There is no justifiable reason +3 points
How do fish circulatory systems work?
- Venous (deoxygenated) enters heart via the sinus venous
- Blood then flows through the sinoatrial valve into the atrium
- Blood then passes through the AV valve into a muscular ventricle
- Blood moves through the bulbal valve into the bulbus arteriosus.
- Blood is pumped through ventral aorta (VA) to the gills
- Now oxygenated blood leaves the gills via dorsal aorta (DA) then returns to heart
What is the difference between the lungfish circulatory and that of a human
- Lungfishes hearts are not completely divided
- They have gills that have little significance in gas exchange
Describe amphibian hearts
- 2 atria, 1 ventricle
1. Blood enters the single ventricle from the two atria
2. Leaves via leaves the ventricle via the conus arteriosus (CA)
3. CA divides into two branches which divide into another two branches, the pulmocutaneous arteries that connect to systemic tissues, lungs and skin
Know this
______: Decreased inspired O2 (PIO2)
______: Increased inspired O2
______: Normal inspired O2
______: Increased inspired CO2 (PICO2)
______: Decreased inspired CO2
______: Normal inspired CO2
Hypoxia
Hyperoxia
Normoxia
Hypercapnia
Hypocapnia
Normocapnia
Who needs to move more water / air through their gills / lungs, water or air breathers and why?
Water breathers need to move more water over their gills than air breathers need to move air over their lungs in order to extract the same amount of oxygen. This is because air has 30x more oxygen than water
What are the three types of respiratory organs?
Lungs, Internal gills and external gills
______ ventilation involves using muscular contraction to move either air or water across the respiratory exchange surface. _____ ventilation involves diffusion of gases across a respiratory surface with no active movement of water or air
Active, Passive
What is the difference between tidal, non-directional and unimodal ventilation?
-Tidal:
Air goes in and comes out along the same pathway (e.g human lungs)
- Unimodal:
Air goes in one direction only - Non-directional:
External gills that are “free-floating” in the respiratory media
How do molluscs breathe?
They have a little funnel that allows water to tidaly ventilate the gills as they move. When their mantle cavity fills with water their muscles contract and force the water out, ventilating the gills.
How do crustaceans breathe?
- pushes water through an anterior opening; creates negative pressure; sucks water through the posterior opening.
For fish breathing:
Water enters through the mouth into the ____ _____. Water then flows across the gills into the ____ _____ and exits via the ___ ___
buccal cavity, opercular cavity, gill slit
For fish breathing:
The direction of water flow between the secondary lamellae is _______ to the direction of blood flow within the secondary lamellae
opposite
What is the difference between obligate and facultative air-breathers?
- Obligate:
Breath air all of the time and do not breathe water
(Salmon) - Facultative:
Breathe water, but when low O2 in water, breathes air (Mudskippers)
How do frogs breathe air?
- Mouth opens, new air flows through nostrils and enters buccal cavity
- Glottis opens, old air flows out lungs via nostrils and top of mouth
- Nares close, new air is pumped into lungs
- The glottis closes. New air is trapped into lungs
Describe reptilian lungs
- They have suction lungs which pull in air
- Develop a negative pressure which causes air flow in-and-out of the lungs
How do birds breathe?
- First inhalation moves air from trachea to posterior sacs
- First exhalation moves air from posterior air sacs into the lungs
- Second inhalation moves air from the lungs into the anterior air sacs
- Second exhalation moves air from air sacs into the trachea and out into the atmosphere
For bird breathing:
The blood vessels that supply the lungs have capillaries that run between an ______ (in) blood vessel and an _____ (out) blood vessel.
afferent, efferent
What is the process of human respiration?
- Breathe in air through nose and/or mouth
- epiglottis opens and air travels through the glottis and down the trachea
- Air travels through the bronchi into the bronchioles
- Air reaches the alveoli sacs which facilitate gas-exchange
The trachea is surrounded by rings of cartilage that make it rigid and prevent its collapse. This rigidity is termed _____ ______
airway patency
What controls the contractions of the diaphragm and what is the purpose of the contractions?
The contractions are caused by the phrenic nerve. They are necessary to increase or decrease internal pressure which causes the lungs to fill with or expel air.
What are the differences between obstructive and restrictive lung diseases?
Restrictive:
- interferes with lung expansion, and thus inspiration
Obstructive:
- These conditions hinder expiration. Since air does not leave the lungs efficiently, the lungs over-inflate
How are lung volumes measured?
Pulmonary function tests
What does the brain utilise to regulate breathing?
Medulla in conjuncture with the spinal cord
What are the four important respiratory control systems?
- Central chemoreceptors
- On brain steam, monitor pH/CO2 levels of spinal fluid - Peripheral oxygen chemoreceptors
- Monitor arterial O2 levels - Pulmonary stretch receptors
- Monitor inflation of lungs - Positional receptor
- In joints, activate when muscles move
What are the four major respiratory centres?
1) The Pre-Bötzinger Complex which is the site of respiratory rhythm generation.
2) The Pontine Respiratory Group (PRG) which terminates inspiration.
3) The Dorsal Respiratory Group (DRG) which is the site of first CNS synapse for a number of peripheral control system inputs.
4) The Ventral Respiratory Group (VRG) which is an important integrative centre.
In mammals,_____ ______ chemoreceptors are located in a structure called the carotid body
arterial oxygen
The cells within the carotid body that sense oxygen are called ______ (type I) cells. The carotid body is innervated by the ____ _____ _____ (CSN).
glomus, carotid sinus nerve
What is the CO2 hydration-dehydration reaction?
- Catalysed by carbonic anhydrase (anti-hydro, thus dehydrate)
- H2O + CO2 <> H2CO3 <> HCO3 + H
Involved in: - CO2 sensing in the brain
- Carbon dioxide and oxygen transport in red blood cells
- Secretion of hydrochloric acid into the stomach
- Acid-base, sodium and potassium regulation in the kidney
What is the significance of the Central (brain) CO2 chemoreceptors?
CO2 diffuses across the blood-brain barrier which enters the CSP. It then undergoes the hydration-dehydration reaction and the reamining [H+] ion reacts with the chemoreceptors in the medulla. This provide the most important stimulus to breathe in all air-breathing animals.
What is the critical component of the Hering-Breuer Inspiratory Off-Switch and what is its’ significance?
The Pulmonary stretch receptors (PSR) recognise when the lungs are fully inflated and then send signals to the brain to begin exhaling.
What makes our breathing rates increase during exercise even though our blood O2, CO2 and pH levels do not change?
We have no fucken clue
How is oxygen carried through the blood?
By hemoglobins which contain Fe, the oxygen binds to that Fe
What is the set of reactions that results from blood flowing through the lungs?
- O2 binds to hemoglobin
- Hemoglobin loses an H+ ion
- H+ reacts with HCO3-
- CO2 and H2O are chemically produced
- CO2 diffuses into alveoli gas
What set of reactions occur when blood flows through tissues?
- CO2 diffuses into RBC
- CO2 reacts with H2O
- H+ and HCO3-
- H+ reacts with Hb*O2
- H+*Hb and O2
- O2 diffuses into tissues
_____ temperatures reduce the binding of oxygen to haemoglobin.
____ temperatures increase the binding of oxygen to haemoglobin.
____ pH reduces the binding of oxygen to haemoglobin.
____ pH increases the binding of oxygen to haemoglobin.
Changes in temperature and pH in the lungs _____ the affinity of haemoglobin for oxygen.
Changes in temperature and pH in the tissues _____ the affinity of haemoglobin for oxygen.
High
Low
Low
High
increase
reduce
What diagram plots the percent of Hb bound with oxygen as a function of the partial pressure of oxygen (PO2) in the blood?
An oxygen equilibrium curve (OEC) diagram
What requires a higher partial pressure to achieve 50% hemoglobin saturation, oxygen or carbon dioxide?
Oxygen, with a pp of 30mm Hg rather than carbon dioxides 1mm Hg.
What does direct calorimetry measure?
Heat production, which can be used as a direct measure of metabolic rate because a byproduct of metabolism is energy release in the form of heat.
Note: The amount of energy required to heat 1 gram of water by 1 degree Celsius is equal to 1 calorie
Metabolic rate can be measured indirectly (by measuring oxygen consumption) using a technique called _____ ________
closed respirometry
In order to measure energy in the feces you use a device called a _____ _____
bomb calorimeter
Poikilotherm vs homeotherm
Poikilotherms body temperatures fluctuate
HOMEOtherms body temperatures stay consistent (HOMEOstasis = maintaining of constant levels, HOMEOtherms = constant temp level)
Ectotherms vs endotherms
ECTOtherms obtain heat via their environement (ecto- = exterior)
ENDOtherms produce their own heat metabolically
(endo- = internal)
There is a range of ambient temperatures called the _______ zone in which metabolic rate is constant.
thermoneutral
When ambient (environmental) temperature goes below a lower-critical temperature or above an upper-critical temperature, metabolic rate _______
increases
Is there an increase in metabolic rate associated with the ingestion and digestion of food?
No
_____ metabolic rate is to ectotherms as _____ metabolic rate is to endotherms
standard, basal
As body weight increases, metabolic rate _____
increases
As animals increase in body weight, the energy needs of 1 gram of tissue ______
decrease
The relationship between metabolic rate and body weight is expressed by what formula?
M = aW^b
Metabolic rate (M) is equal to a constant (a) times body weight (W) to the exponent “b” (another constant).
What are the four types of heat exchange?
- Conduction - Direct contact heat transfer
- Convection - Direct heat transfer from water or air
- Radiation - Heat transfer between objects not in contact with eachother
- Evaporative heat loss - Loss of heat through skin or ciruclatory system
Give a few examples of how ectotherms regulate their body temperature
They may bask in sun for heat and burrow underground to cool off
How do some animals such as wood frogs manage to sustain being legit frozen solid for extended periods of time?
They contain higher levels of urea, alcohol and/or glucose which act as cryoprotectants. These allow the extracellular fluid to freeze but not the intracellular fluid. Some animals also produce special peptides which act as antifreezes which prevent ice spread. Preventing freezing is important because ice will actually draw water out of cells and kill them so limitting the amount of ice that can build up in their systems allows them to survive.
Note incase they ask some BS uber-specific question: Frogs metabolism and heartrate comes to a near halt during these frozen periods. How do they survive? No clue man
What part of the brain is in charge of thermoregulation?
Hypothalamus, which senses changes of blood temperature and reacts according
What are some measures the body takes in order to restore temperature after dropping BELOW the set-point?
- Shivering thermogenesis which burns calories and thus creates heat as a byproduct of energy consumption
- Blood vessels constrict and blood is diverted to deeper tissues; reduces heat loss at cutaneous level
- Brown adipose tissue (BAT, found in newborns and hibernating animals) contain increase mitochondria and respond to noradrenaline and produce heat via reactions
What are some measures the body takes in order to restore temperature after rising ABOVE the set-point?
- Sweating which consumes body heat to evaporate the water from your skin
- Vessels dilate and blood is diverted towards the cutaneous layer, increases heat loss through pores
Describe temperature cycling
Instead of maintaining a constant body temperature some animals build up heat overtime and then expel it later on. Such as camels which accumulate heat during the day and then cool off at night.
Describe temperature cycling
Instead of maintaining a constant body temperature some animals build up heat overtime and then expel it later on. Such as camels which accumulate heat during the day and then cool off at night.
How does brain cooling work?
Blood from the brain flows through the jugular which flows into the carotid artery. It passes through the venous sinus system which cools down the blood because of the colder air that is inhaled through your nose.
How can heterotherms deliberately alter their body temperatures?
Turpor (the shorter & less powerful version of hibernation) or hibernation
Describe osmotic pressure
The pressure that draws water from areas of high-water;low-solute conc. to areas of low-water;high-solute conc
Animals that live in water can either ________ (and keep their body fluids at an osmotic pressure that is different from that in the water) or they can ________ (and keep their body fluids at the same concentration as that of the water in which they live)
osmoregulate (costs energy), osmoconform (does not)
Freshwater fish tend to ____ water via osmosis and _____ ions via diffusion, whereas saltwater fish tend to ____ water and _____ ions
gain, lose, lose, gain
What do fresh-water fish use to take up nutrients from water?
- Sodium-proton exchanger to take up sodium in exchange for a proton
- Chloride-bicarbonate exchanger to take-up chloride in exchange for a bicarbonate ion
How do saltwater fish excrete ions?
- Feces and through gills
- K+ and Na+ pumps im not memorising that shit
What are the two sectors of the digestive system?
- Digestive tract
- Accessory organs
What are the three types of salivary gland and where are they located?
Parotoid: Sides of the head under the cheek
Sublingual: Under the tongue
Submandibular: Under lower jaw
How does saliva benefit you?
Bicarbonate within it helps to neutralise acids, salivary amylase helps breakdown food. Mucous provides lubrication. Lysozyme breaks down bacteria
Describe the esophagus
A pipe with an upper and lower sphincter. Upper allows food passage into esophagus, lower allows passage into stomach
Describe a haitial hernia
Hernia growth that grows unorthodically above the diaphragm , can lead to acid buildup in esophagus. Not good
The upper region of the stomach (the part that sits above the opening of the esophagus into the stomach) is called the _____. The main part of the stomach is called the body and the horizontal part that leads to the duodenum is called the ______. The stomach is lined with folds call _______ that stretch and flatten out when the stomach fills. This increases the surface area of the stomach.
fundus, antrum, rugae
In the stomach:
______ cells secrete hydrochloric acid (HCl). ______ cells secrete pepsinogen which is then converted into its active form called pepsin. These are secreted by pores call gastric pits
Parietal, Chief
What is Helicobacter pylori?
A bacteria that breaks down stomach lining and can lead to stomach ulcers
What is the food pathway through the small intestine?
- duodenum
- jejunum
- Ileum
- Illeocecal valve
What is the food pathway through the large intestine?
- Cecum
- Ascending colon (UP)
- Transverse colon (SIDEWAYS)
- Descending colon (DOWN)
- Sigmoid colon
- Rectum
- Anal sphincter
