Docsity
Log inSign up
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search Store documents

The best documents sold by students who completed their studies

Search through all study resources
Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

University Rankings

Discover the best universities in your country according to Docsity users

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

From our blog

Exams and Study
Go to the blog

Blood Flow and Gas Exchange in Animals: Anatomy and Physiology - Prof. Ray Spear, Study notes of Biology

State University of New York at Geneseo (SUNY)Biology
Prof. Ray Spear

The mechanisms of blood flow and gas exchange in animals, focusing on the role of capillaries, the lymphatic system, and the effects of partial pressure gradients. It also covers the differences between respiratory systems in various organisms, such as fish gills and insect tracheal systems.

Typology: Study notes

2011/2012

Uploaded on 05/13/2012

erikaschoene
erikaschoene 🇺🇸

11 documents

1 / 8

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
2/8/2012
1
Circulation & Gas Exchange
Reminders
•Exam on Friday
•Bring a sharpened #2 pencil to the exam
•40-45 multiple choice questions covering all
material from lectures & reading notes
Organisms in which a circulating body fluid is distinct
from the fluid that directly surrounds the body’s cells
are likely to have which of the following?
•A. An open circulatory system
•B. A closed circulatory system
•C. A gastrovascular cavity
•D. Branched trachea
•E. hemolymph
Which of the following are the only vertebrates in
which blood flows directly from respiratory organs to
body tissues without first returning to the heart?
•A. Amphibians
•B. Birds
•C. Fishes
•D. Mammals
•E. Reptiles
Blood Pressure & the physics of fluids in
pipes
•Blood flow slows down as it moves arteries →
arterioles → capillaries
–Volume of flow per second always remains the
same thru a pipe
•Law of continuity:
•If pipe diameter Δs along its length:
–Narrower pipes: faster flow
–Wider pipes: slower flow
Blood Flow Velocity
•Physical laws governing
movement of fluids
through pipes affect blood
flow and blood pressure
•Velocity of blood flow is
slowest in the capillary
beds, as a result of the
high resistance and large
total cross-sectional area
LE 42-11
Systolic
pressure
Venaecavae
Veins
Venules
Capillaries
Arterioles
Arteries
Aorta
Diastolic
pressure
Pressure (mm Hg)
120
100
80
60
40
20
0
Area (cm2)
5,000
4,000
3,000
2,000
1,000
0
Velocity (cm/sec)
50
40
30
20
10
0
pf3
pf4
pf5
pf8

Partial preview of the text

Download Blood Flow and Gas Exchange in Animals: Anatomy and Physiology - Prof. Ray Spear and more Study notes Biology in PDF only on Docsity!

Circulation & Gas Exchange

Reminders

  • Exam on Friday
  • Bring a sharpened #2 pencil to the exam
  • 40 - 45 multiple choice questions covering all

material from lectures & reading notes

Organisms in which a circulating body fluid is distinct

from the fluid that directly surrounds the body’s cells

are likely to have which of the following?

  • A. An open circulatory system
  • B. A closed circulatory system
  • C. A gastrovascular cavity
  • D. Branched trachea
  • E. hemolymph

Which of the following are the only vertebrates in

which blood flows directly from respiratory organs to

body tissues without first returning to the heart?

  • A. Amphibians
  • B. Birds
  • C. Fishes
  • D. Mammals
  • E. Reptiles

Blood Pressure & the physics of fluids in

pipes

  • Blood flow slows down as it moves arteries →

arterioles → capillaries

  • Volume of flow per second always remains the same thru a pipe
  • Law of continuity:
  • If pipe diameter Δs along its length:
  • Narrower pipes: faster flow
  • Wider pipes: slower flow

Blood Flow Velocity

  • Physical laws governing movement of fluids through pipes affect blood flow and blood pressure
  • Velocity of blood flow is slowest in the capillary beds, as a result of the high resistance and large total cross-sectional area LE 42- Systolicpressure Venae cavae VenulesVeins ArteriesArteriolesCapillaries Aorta Diastolicpressure Pressure (mm Hg) (^120100) (^8060) (^4020) 0 Area (cm 2 )^ 5,0004, 3,0002, 1,000 0 Velocity (cm/sec) (^5040) (^3020) (^100)

Capillary Function

  • Blood flows through only 510% of the body’s capillaries at a time
  • Capillaries in major organs are usually filled to capacity
  • Blood supply varies in many other sites © 2011 Pearson Education, Inc.
  • Two mechanisms regulate distribution of blood in capillary beds
  • Contraction of the smooth muscle layer in the wall of an arteriole constricts the vessel
  • Precapillary sphincters control flow of blood between arterioles and venules
  • Blood flow is regulated by nerve impulses, hormones, and other chemicals © 2011 Pearson Education, Inc. Figure 42.14 Precapillary sphincters^ Thoroughfare channel Arteriole Capillaries Venule (a) Sphincters relaxed Arteriole Venule (b) Sphincters contracted
  • Capillary exchange
  • Transfer of gases, nutrients, wastes btwn blood & interstitial fluid
  • Net flow OUT of capillary @ arteriole end
  • Net flow IN to capillary @ venule end
  • Vessicles, diffusion, bulk flow(thru clefts btwn cells) Precapillary sphincters Thoroughfare channel Arteriole Capillaries^ Venule Sphincters relaxed Arteriole Venule Sphincters contracted
  • The exchange of substances between the blood and interstitial fluid takes place across the thin endothelial walls of the capillaries
  • The difference between blood pressure and osmotic pressure drives fluids out of capillaries at the arteriole end and into capillaries at the venule end
  • Most blood proteins and all blood cells are too large to pass through the endothelium © 2011 Pearson Education, Inc. Figure 42. INTERSTITIAL FLUID Net fluid movement out Blood pressure Osmotic pressure Arterial end of capillary Direction of blood flow Venous end of capillary Body cell

Gas Exchange

  • Animals require O 2 uptake, CO 2 discharge b/c of cellular respiration
  • Respiratory surface must always be moist/wet
  • CO 2 , O 2 dissolve in water → diffuse across plasma membrane
  • SA:V important for gas exchange
    • How to increase SA:V ratio in gills, lungs?

Gas Exchange in an aqueous

environment

  • What are advantages & disadvantages of

respiring in water?

      • Respiratory surface always moist
      • CO2 discharge easy b/c ↑ solubility
      • [O 2 ]water < [O 2 ]air
      • ↑ Salts (solutes) or ↑ temp – ↓ [O 2 ]

Gills

  • Aquatic animals
  • Diversity of gill structures across taxa
  • Ventilation: ↑ flow of water over respiratory surfaces
  • Countercurrent exchange in fish

Fish Gills

  • Ventilation moves the respiratory medium over the respiratory surface
  • Aquatic animals move through water or move water over their gills for ventilation
  • Fish gills use a countercurrent exchange system, where blood flows in the opposite direction to water passing over the gills; blood is always less saturated with O 2 than the water it meets © 2011 Pearson Education, Inc. Figure 42. Gill arch O 2 - poor blood O 2 - rich blood Blood vessels Gill arch Water flow Operculum Water flow (^) Blood flow Countercurrent exchange P O 2 (mm Hg) in water (^150) PO (mm Hg) in blood^2 120 90 60 30 Net diffu sion of O- 2 140 110 80 50 20 Lamella Gill filaments

Gill arch Water flow Operculum Blood vessels Gill arch Gill filaments Figure 42.23a (^) O 2 - poor blood Water flow (^) Blood flow Countercurrent exchange PO 2 (mm Hg) in water 150 PO (mm Hg) in blood^2 Net diffu sion of O- 2 140 Lamella O 2 - rich blood 120 90 60 30 110 80 50 20 Figure 42.23b

Countercurrent gas exchange Tracheal Systems in Insects

  • The tracheal system of insects consists of tiny branching tubes that penetrate the body
  • The tracheal tubes supply O 2 directly to body cells
  • The respiratory and circulatory systems are separate
  • Larger insects must ventilate their tracheal system to meet O 2 demands © 2011 Pearson Education, Inc. Tracheoles Mitochondria Muscle fiber

m Tracheae Air sacs External opening Trachea Air sac Tracheole Body cell Air Figure 42.

Lungs

  • Lungs are an infolding of the body surface
  • The circulatory system (open or closed) transports gases between the lungs and the rest of the body
  • The size and complexity of lungs correlate with an animal’s metabolic rate © 2011 Pearson Education, Inc.

Coordination of Circulation and Gas Exchange

  • Blood arriving in the lungs has a low partial pressure of O 2 and a high partial pressure of CO 2 relative to air in the alveoli
  • In the alveoli, O 2 diffuses into the blood and CO 2 diffuses into the air
  • In tissue capillaries, partial pressure gradients favor diffusion of O 2 into the interstitial fluids and CO 2 into the blood © 2011 Pearson Education, Inc. Exhaled air Inhaled air Pulmonary arteries Systemic veins Systemic arteries Pulmonary veins Alveolar capillaries Alveolar^ Alveolar^ spaces epithelial cells Inhaled air 160 120 80 40 Heart^0 8 1 2 3 6 4 7 CO 2 O 2 Systemic capillaries CO 2 O (^25) Body tissue (a) The path of respiratory gases in the circulatory system (b) Partial pressure of O circulatory system numbered in (a) 2 and CO 2 at different points in the 1 2 3 4 5 6 7 Exhaled air Partial pressure (mm Hg) P POCO (^2) 2 8 Figure 42. Respiratory Pigments
  • Respiratory pigments, proteins that transport oxygen, greatly increase the amount of oxygen that blood can carry
  • Arthropods and many molluscs have hemocyanin with copper as the oxygen-binding component
  • Most vertebrates and some invertebrates use hemoglobin
  • In vertebrates, hemoglobin is contained within erythrocytes (red blood cells) © 2011 Pearson Education, Inc. Hemoglobin
  • A single hemoglobin molecule can carry four molecules of O 2 , one molecule for each iron- containing heme group
  • The hemoglobin dissociation curve shows that a small change in the partial pressure of oxygen can result in a large change in delivery of O 2
  • CO 2 produced during cellular respiration lowers blood pH and decreases the affinity of hemoglobin for O 2 ; this is called the Bohr shift © 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc. Figure 42.UN Iron Heme Hemoglobin Figure 42. (a) PO 2 and hemoglobin dissociation at pH 7. Tissues during exercise Tissues at rest Lungs PO (mm Hg) 2 (b) pH and hemoglobin dissociation PO (mm Hg) 2 (^00 20 40 60 80 ) 20 40 60 80 100 (^00 20 40 60 80 ) 20 40 60 80 100 Hemoglobin retains less O 2 at lower pH (higher CO concentration) 2 pH 7. pH 7. O 2 unloaded during exercise^ to tissues Osaturation of hemoglobin (%)^2 O to tissues 2 unloaded at rest Osaturation of hemoglobin (%)^2

Figure 42.31a (a) PO 2 and hemoglobin dissociation at pH 7. Tissues during exercise Tissues at rest Lungs PO (mm Hg) 2 0 20 40 60 80 100 0 20 40 60 80 100 O 2 unloaded to tissues during exercise O 2 unloaded to tissues at rest O^2 saturation of hemoglobin (%) Hemoglobin releases about 30% of the bound O2 to tissues @ rest The added metabolic demand of exercise results in release of

80% of bound O (b) pH and hemoglobin dissociation PO 2 (mm Hg) 0 20 40 60 80 100 0 20 40 60 80 100 Hemoglobin retains less O 2 at lower pH (higher CO 2 concentration) pH 7. pH 7. O^2 saturation of hemoglobin (%) Figure 42.31b In very active tissues (eg. during

extended exercise) efficiency of O release is increased by the Bohr shift. Increased CO decreases the pH of blood, shifting the curve to the right.