case 1
learning goals
1. What is the composition and function of blood? (interstitial fluid) (plasma)
2. How are the blood cells produced?
3. How are nutrients transported? (what are the differences between transport
systems?) (not cell-to-cell, but transport across membranes)
4. How is the blood pumped through the body? Not too detailed (veins, arteries,
capillaries)
5. How does the fluid flow through the capillary walls? (arterial and venous end)
- presentations: LG2 and LG3 (just a brief overview of the different transport
mechanisms)
1.What is the composition and function of blood? (interstitial fluid) (plasma)
overview
,- blood is the circulating portion of the extracellular fluid, responsible for carrying
material from one part of the body to another
- 2 main fluid compartments:
- extracellular fluid: outside the cells
- plasma
- interstitial fluid
- intracellular fluid: surrounds most cells of the body
,general function of blood
- distribution: oxygen, metabolic waste products, hormones
- regulation: body temperature, pH, adequate fluid volume
- protection: preventing blood loss, preventing infection
erythrocytes, red blood cells
- have lost their nuclei by the time they enter the bloodstream
- play a key role in transporting oxygen from lungs to tissues, and carbon dioxide from
tissues to lungs
- most abundant cell type in the blood
- hematocrit: indicates the ratio of red blood cells to plasma, expressed as a
percentage of the total blood volume
- determined by drawing a blood sample into a narrow capillary tube and
spinning it in a centrifuge so that the heavier red blood cells go to the bottom
of the sealed tube, leaving the thin buffy layer of lighter white blood cells and
platelets in the middle, and plasma on top
- biconcave disks: simple membranous bags filled with enzymes and hemoglobin
- the membrane is held in place by a complex cytoskeleton composed of filaments
linked to transmembrane attachment proteins
- RBCs are remarkably flexible, despite the cytoskeleton → allows RBCs to change
shape as they squeeze through the narrow capillaries of the circulation
- no mitochondria → RBCs cannot carry out aerobic metabolism → glycolysis is their
primary source of ATP
- RBCs are unable to make new enzymes or to renew membrane components
because they have no nucleus and endoplasmic reticulum to carry out protein
synthesis. This leads to an increasing loss of membrane flexibility, making older cells
more fragile and likely to rupture
- RBCs can modify their shape in response to osmotic changes in the blood
- hypertonic media: RBCs shrink up and develop a spiky surface when the
membrane pulls tight against the cytoskeleton
- hypotonic media: RBCs swells and forms a sphere without disruption of its
membrane integrity
, - hemoglobin
- main component of RBCs
- role in oxygen transport
- large, complex protein with 4 globular protein chains, each of which is
wrapped around an iron-containing heme group
- several isoforms
- most common isoforms are designated alpha, beta, gamma, and
delta, depending on the structure of the chain
- designated HbA: most adult hemoglobin, two alpha chains and two
beta chains
- HbA2: small portion of adult hemoglobin, two alpha chains and two
delta chains
- heme groups
- the 4 heme groups in a hemoglobin molecule are identical
- each consists of a carbon-hydrogen-nitrogen porphyrin ring with an
iron atom (Fe) in the center
- anemia: too low hemoglobin content → blood cannot transport enough oxygen
to the tissue
learning goals
1. What is the composition and function of blood? (interstitial fluid) (plasma)
2. How are the blood cells produced?
3. How are nutrients transported? (what are the differences between transport
systems?) (not cell-to-cell, but transport across membranes)
4. How is the blood pumped through the body? Not too detailed (veins, arteries,
capillaries)
5. How does the fluid flow through the capillary walls? (arterial and venous end)
- presentations: LG2 and LG3 (just a brief overview of the different transport
mechanisms)
1.What is the composition and function of blood? (interstitial fluid) (plasma)
overview
,- blood is the circulating portion of the extracellular fluid, responsible for carrying
material from one part of the body to another
- 2 main fluid compartments:
- extracellular fluid: outside the cells
- plasma
- interstitial fluid
- intracellular fluid: surrounds most cells of the body
,general function of blood
- distribution: oxygen, metabolic waste products, hormones
- regulation: body temperature, pH, adequate fluid volume
- protection: preventing blood loss, preventing infection
erythrocytes, red blood cells
- have lost their nuclei by the time they enter the bloodstream
- play a key role in transporting oxygen from lungs to tissues, and carbon dioxide from
tissues to lungs
- most abundant cell type in the blood
- hematocrit: indicates the ratio of red blood cells to plasma, expressed as a
percentage of the total blood volume
- determined by drawing a blood sample into a narrow capillary tube and
spinning it in a centrifuge so that the heavier red blood cells go to the bottom
of the sealed tube, leaving the thin buffy layer of lighter white blood cells and
platelets in the middle, and plasma on top
- biconcave disks: simple membranous bags filled with enzymes and hemoglobin
- the membrane is held in place by a complex cytoskeleton composed of filaments
linked to transmembrane attachment proteins
- RBCs are remarkably flexible, despite the cytoskeleton → allows RBCs to change
shape as they squeeze through the narrow capillaries of the circulation
- no mitochondria → RBCs cannot carry out aerobic metabolism → glycolysis is their
primary source of ATP
- RBCs are unable to make new enzymes or to renew membrane components
because they have no nucleus and endoplasmic reticulum to carry out protein
synthesis. This leads to an increasing loss of membrane flexibility, making older cells
more fragile and likely to rupture
- RBCs can modify their shape in response to osmotic changes in the blood
- hypertonic media: RBCs shrink up and develop a spiky surface when the
membrane pulls tight against the cytoskeleton
- hypotonic media: RBCs swells and forms a sphere without disruption of its
membrane integrity
, - hemoglobin
- main component of RBCs
- role in oxygen transport
- large, complex protein with 4 globular protein chains, each of which is
wrapped around an iron-containing heme group
- several isoforms
- most common isoforms are designated alpha, beta, gamma, and
delta, depending on the structure of the chain
- designated HbA: most adult hemoglobin, two alpha chains and two
beta chains
- HbA2: small portion of adult hemoglobin, two alpha chains and two
delta chains
- heme groups
- the 4 heme groups in a hemoglobin molecule are identical
- each consists of a carbon-hydrogen-nitrogen porphyrin ring with an
iron atom (Fe) in the center
- anemia: too low hemoglobin content → blood cannot transport enough oxygen
to the tissue
