FINAL EXAM REVIEW Flashcards
What is the progression of parts used in the human circulatory system?
Arteries –>Arterioles–>capillaries–>Venules–>veins
What are Arteries?
-They are vessels that lead AWAY from the heart
What are Veins?
-They are large vessels leading INTO the heart
What are arteries and veins connected by?
-Capillary bed= where gas & fluid are exchanged
What are the 2 bodily circuits
- Pulmonary
- Systemic
What is the role of the Pulmonary Circuit?
-It is the route of blood to the lungs and back
What is the role of the systemic circuit?
-It is the route of blood to the tissues and back
What is the gas exchange like in the lungs (PO2 and PCO2)?
- The PO2 in the air is higher than the PO2 in lungs so O2 enters the blood from the air
- The PCO2 in the lung capillaries is higher than the PCO2 in the air so CO2 moves from lung capillaries into the air
What is PO2?
-The pressure of oxygen
What is PCO2?
-Pressure of carbon dioxide
What is gas exchange like in the tissues?
- O2 is used to lower the PO2 which forces the O2 from the capillaries into the tissues
- CO2 is generated by tissues= higher PCO2 which forces the CO2 from tissues into the capillaries
How is the soluability like of O2 in water?
-Relatively low
What shape is the hemoglobin O2 binding curve and what does it mean?
-Sigmoid shaped which means that there is cooperative O2 binding
How many O2 molecules can bind to hemoglobin?
4= one for each globin chain/ heme group
What does cooperativity mean in terms of O2 binding to hemoglobin?
- The first O2 is slower to bind than the ones after it
- The last O2 also binds more slowly bc there’s only one space left for it to bind
What occurs when the first O2 binds to hemoglobin?
-It changes the shape=Allosteric Interactions of the molecule so that the 2 O2 molecules that bind after it bind easily & makes the hemoglobin the Allosteric protein
Are all Allosteric Interactions cooperative?
-NO
What is the hemoglobin like in fetuses & llamas?
-It has a binding curve that is left-shifted
What does the left-shifted curve in hemoglobin result in?
-Saturation of lower PO2= adaptation to lower O2 environments
What are the 2 types of conducting tissues in plants?
- Xylem
- Phloem
What is the Xylem tissue made of?
-It is dead=consists of Tracheids
What are Tracheids?
-They are cells that die which leaves only hollow tubes made up of cell wall material
What is Phloem tissue made of?
-It is made up of alive sieve cells
How do plants move water?
-VIA water potential= pumping ions across the membrane
How does water always flow in plant transport?
-From areas of high to areas of low water potential
What are the 2 pathways that allow water to enter the root?
- Symplast
- Apoplast pathways
What is the Apoplast pathway like?
- It’s passive and non-selective
- Water diffuses between cells by capillary action through the spaces between the cell walls=inhibition
- Water doesn’t enter through the cells=doesn’t even involve the xylem
What is the Apoplast pathway prevented from reaching?
-It can’t reach the stele bc the casperian strip is there
What is the Casperian Strip?
-It is a region of the cell wall that has hella hydrophobic substance which seals off the stele
Which water conduction pathway makes it to the Xylem?
-The symplast pathway
What is the Symplast pathway like?
- Minerals are actively transported across the membrane due to changes in water potential
- It enforces selectivity in mineral uptake
How does water and minerals move in between cells once they make it across the membrane?
-Via plasmodesmata= allows the flow of cytoplasm in between the cells
How can water move between Apoplast and Symplast pathways?
-By just crossing the membrane
How does water move up the xylem?
-Via tension & cohesion
How is water lost from the leaf?
-Transpiration= creates tension in the column of water in the xylem
How can we tell that water is being pulled up the xylem?
-The transpiring diameter of the xylem is less than the non-transpiring diameter= causes the xylem to collapse slightly
What will happen if we were to puncture the Xylem when water is being pulled up in it?
-Water doesn’t squirt out SO the level falls as the diameter of the xylem increases due to the lack of tension
What part of the plant controls gas exchange?
-The stomata
What is the Stomata made of?
-2 guard cells= their shape changes w/ water content
What happens when the Guard Cells are full of water?
-The stomata opens
What happens when the Guard Cells don’t have enough water?
-The stomata is closed
How does the plant respond when soil moisture is low?
-It produces Abscisic acid= causes guard cells to lose water and stomata to close
How are plants mediated when they are actively photosynthesizing?
-The sensing system ties the level of CO2 to the state of the stomata
How does the sensing system work when mediating photosynthesis in the plant?
- When CO2 levels are low, K+ is actively transported into the Guard Cells. This transport lowers Ys in guard cells & allows them to take up the water= opens stomata
- This process is reversed in plants w/ higher CO2 levels
When are CO2 levels low in a plant?
-When the plant is actively photosynthesizing
What is the main difference between transport in the phloem and in the xylem?
-Phloem needs the participation of cells at both ends of any transport events
How does photosynthesis affect the Phloem?
-The photosynthetic sugars are actively transported in phloem which reduces its water potential which then builds up pressure= creates areas of higher pressure in photosynthetic areas & reducing it in non-photosynthetic areas
What are the 2 organizing principles in Physiology?
- Organisms show a hierarchical organization going from cells to tissues to organs to organ systems
- Organisms show homeostasis
What is the organizing principle of organisms having hierarchial organization?
-The organization leads to emergent properties where higher levels show more characteristics than the lower levels (epidermis)
What is homeostasis principle of organisms?
-Allows organisms to maintain a constant internal environment despite the external environment changing
What happens when the levels rise above the set point in homeostasis?
-There is a lowering in response
What happens when the levels plunge below the set point in homeostasis?
-There is a raising response
What are hormones?
-They are chemicals secreted by endocrine cells/ glands into the blood for transport to a distant target
When are hormones the most effective?
-At extremely low concentrations
What must the cell have in order to generate response in the cell?
-Receptors to the specific hormone (membrane-bound or intracellular)
What is the role of the hypothalamus to regulate hormones?
- It integrates information about the physiological state of the organism
- It also generates the inhibiting/ releasing hormone and nerve signals to the pituitary
Where is the pituitary gland located?
-underneath the hypothalamus and consists of anterior and posterior lobe
What is the posterior pituitary gland?
-It is part of the CNS and connected to the hypothalamus by axons from the hypothalamus
What is the role of the posterior pituitary gland?
-It receives neurohormones by the hypothalamus and stores them until needed
What is the anterior pituitary gland?
- NOT part of CNS
- It is formed from an upgrowth of tissue from the palate
What is the role of the anterior pituitary gland?
-It receives hormonal signals from the hypothalamus & then will secrete additional hormones that it made. these hormones are intended to regulate the variables the hypothalamus assessed
What are stress hormones?
- Helps me mobilize my energy stores and increase efficiency in responsiveness
- Their secretion is increased when i’m exposed to stressors like demands/threats
Where are stress hormones produced?
-In the adrenal gland on the kidney
What steroid hormone does the cortex produce?
-Cortisol= acts over longer time scale
What non-steroid hormone does the medulla produce?
- Epinephrine (adrenaline)
- Norepinephrine (noradrenaline)
What is Adrenaline involved in?
-generating fight or flight responses= causes increase in heart/ respiratory rate, increase in blood pressure, decrease in digestive rates, increase in blood glucose levels
What is Cortisol involved in?
- Increase mobilization of energy stores in fat, muscle, and bone
- It suppresses the immune system function & reproduction
How does your body regulate blood sugar?
-By the action of antagonistic hormones
What is the role of the hormone insulin?
-Acts to lower blood sugar by causing cells to take up glucose convert it to glycogen and reduce the rate of glucogenesis in the liver
What is the role of the hormone glucagon?
-It acts to raise blood sugar by causing cells to convert glucagon to glucose which increases the rate of glucogenesis
How does the hormone insulin work?
-It acts as a catalytic receptor
How does the hormone Glucagon work?
-it binds to membrane receptors and initiates signal transduction cascades
How can the blood sugar regulation be overridden by the stress of extreme circumstances?
-It can be overridden by the action of adrenaline
How does Adrenaline work to override blood sugar regulation?
-it binds to a G-protein coupled receptor that acts through the effector adenylyl cyclase to activate PKA
What happens to the PKA after it been activated by Adrenaline?
-It phosphorylates phosphorylase kinase and then phosphorylase kinase phosphorylates glycogen phosphorylase
How is glucose secreted?
-After glycogen phosphorylase cleaves glucose units off the glucose polymer which then adds a phosphate in the process of releasing glucose-1-phosphate
What is the constant level that Ca++ maintained in blood plasma?
10 mg/ml
What role does Ca++ play?
-It is an important signaling molecule that’s essential for cell regulation
How is the level of Ca++ maintained?
-It is controlled by 2 hormones that have antagonistic properties= Calcitonin and Parathyroid
What is the role of Calcitonin in maintaining the Ca++ level?
-It decreases plasma Ca++
What is the role of Parathyroid in maintaining Ca++ levels?
-It increases Plasma Ca++
When does sex differentiation occur?
-6 weeks post-fertilization
What reproductive structures form in males 6-weeks post-fertilization?
-Wolffian ducts
What reproductive structures form in females 6-weeks post-fertilization?
-Mullerian ducts
What do the Wolffian ducts to the Mullerian ducts?
-They inhibit the mullerian ducts when sertoli cells in the testes secrete Mullerian Inhibiting Substance (MIS)
What are endocrine disruptors?
-They are chemicals in the environment that interfere with normal endocrine signaling bc they mimic steroid hormones
What are examples of endocrine disruptors?
- BPA
- DES
What happens when males are exposed to endocrine disruptors during development?
-It causes males to have femininized reproductive organs, undescended testes,and abnormal development of the penis and urethra
What happens when females are exposed to endocrine disruptors during development?
-Causes abnormal development in the reproductive tract= causing T-shaped uterus and an increased risk of developing uterine and cervical cancer
