Lecture 11 Cellular Responses to Hypoxia and Changes in Temperature

Lecture 11 Cellular Responses to Hypoxia and Changes in Temperature

Info iconThis preview shows pages 1–20. Sign up to view the full content.

View Full Document Right Arrow Icon
IPHY 3060 Lecture 11: Cellular Responses to Hypoxia and Changes in Temperature
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Key Points from Before: ATP is produced by the breakdown of food substrates by oxidative phosphorylation, which requires oxygen as the final electron acceptor in the electron transport chain Glycolysis, the initial breakdown of glucose to form pyruvate and 2 ATPs, occurs in the absence of oxygen Oxygen is the final electron acceptor in the electron transport chain; without it, electron and H+ transport, and ATP synthesis are impaired
Background image of page 2
What happens if the cell does not receive enough oxygen?
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Hypoxia:
Background image of page 4
Hypoxia: A condition characterized by low levels of oxygen
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Hypoxia is a hallmark of many environmental conditions High altitude Diving Hibernation
Background image of page 6
Hypoxia is a hallmark of many disease states Peripheral vascular disease Emphysema   Sleep apnea Cancer
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Hypoxia adversely affects electron transport and ATP synthesis
Background image of page 8
Hypoxia adversely affects electron transport and ATP synthesis No O2—ETC is impaired, ATP synthesis is impaired
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Key Point: Hypoxia induces several cellular responses designed to both allow the cell to carry on without oxygen as well as to increase the amount of oxygen delivered
Background image of page 10
Hypoxia Induces Several Responses from Cells: Hypoxia
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Glycolytic Enzymes Increases production of ATP in the absence of O2 Rapid response —hours to days
Background image of page 12
NOS—nitric oxide synthase Increases production of nitric oxide or NO NO causes smooth muscle cells to relax Opens vessels wider, lets more blood through— increased blood delivery, increased O2 delivery Immediately increases oxygen delivery—within minutes/hours
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
VEGF—vascular endothelial growth factor Increases angiogenesis , formation of new blood vessels Decreases diffusion distance from blood vessels to cells, which increases O2 delivery Increases oxygen delivery over the long term—days to weeks
Background image of page 14
Erythropoietin Increases red blood cell formation More blood carrying capacity of oxygen per unit blood, increases O2 delivery Increases oxygen delivery over the long term—days to weeks
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Erythropoietin and Medicine Gene was cloned by Amgen in 1983 Synthetically produced EPO first approved for humans in 1989 Is used to treat patients with anemia resulting from kidney failure, cancer, and AIDs Total sales for EPO were over 8 billion dollars in 2004
Background image of page 16
Erythropoietin—a performance enhancing substance Erythropoietin can increase RBC content (hematocrit) in athletes and thus O 2 delivery by the blood EPO doping thus improves performance of endurance type sporting events—cycling, cross country skiing, distance running, swimming EPO can provide up to a 3-5% improvement in endurance sport performance Until 2000 the only way to test for EPO was to examine hematocrit There is currently a blood and a urine test for EPO but it isn’t totally accepted Excessive hematocrit can cause blood to become lethally viscous-- polychthemia
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Hypoxia Induces These Responses by Activating the Hif-1alpha Transcription Factor Hypoxia Hif-1alpha
Background image of page 18
Hypoxia-induced Genes Step 1: Hif-1alpha is ordinarily degraded by a protease as soon as it is formed Hif-1
Background image of page 19

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 20
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 60

Lecture 11 Cellular Responses to Hypoxia and Changes in Temperature

This preview shows document pages 1 - 20. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online