Lecture 5 - Cardiovascular System I Flashcards
1
Q
Cardiovascular System - 3 parts
A
- Heart
- Blood vessels
- Blood
2
Q
Blood
A
- Type of connective tissue
- Plasma (55%) and cells (45%)
- 7% of body weight
- Adult males 5.6L, Adult females 4.5L
3
Q
Functions of Blood
A
- Transport O2, CO2, nutrients, waste, hormones
- Regulate pH, temperature
- Immune function - antibodies, phagocytes, clotting factors
4
Q
Blood Plasma - composition
A
- Water (91%)
- Proteins (7%)
- Mineral salts (0.9%)
- Nutrients
- Organic waste
- Hormones
- Enzymes
- Gases
5
Q
Blood Plasma PROTEINS
A
Synthesised by liver cells (hepatocytes)
- Albumin
- Globulin
- Fibrinogen
6
Q
Albumin
A
Blood plasma protein
- Smallest and most numerous
- Carries lipids and steroid hormones
- Maintains osmotic pressure
7
Q
Globulin
A
Blood plasma protein (accounts for 38%)
- Immunity - immunoglobulins (antibodies) secreted by B cells
- Transport - iron, lipids, vitamins
8
Q
Fibrinogen
A
Blood plasma protein (7%)
- Also called ‘clotting factor one’
- Essential for blood clotting
9
Q
Blood plasma nutrients
A
- Simple sugars (carbohydrates) - most glucose
- Amino acids
- Fats/oils
- Vitamins
- Minerals
10
Q
Minerals in blood plasma
A
-
Cations (positively charged ions)
- Sodium, potassium, calcium, magnesium
-
Anions (negatively charged ions)
- Chlorides, bicarbonates, phosphates
11
Q
Organic waste in blood plasma
A
- Urea - from protein breakdown
- Creatinine - from muscle metabolism
- Uric acid - from purine breakdown
- Carbon dioxide - from cell metabolism
12
Q
What are hormomes?
A
Chemical messengers carried by the blood
13
Q
What are enzymes?
A
- Catalysts for chemical reactions in the body
- Type of protein
14
Q
3 types of blood cells
A
- Erythrocytes - red blood cells
- Leukocytes - white blood cells
- Thromocytes - platelets
15
Q
Haematopoeisis
A
- Pluripotent cells - all blood cells originate
- First 2 months of gestation - embryonic yolk sac performs haematopoiesis
- Between 2-9 months foetal life - liver and spleen take over
- First few years of life - all bone marrow is red and produces blood cells
- Adults - haematopoeisis in vertebrae, ribs, sternum, skull, sacrum, pelvis and femur
16
Q
Erythrocytes
A
- Bi-concave and no nucleus - larger surface area to transport O2
- Lifespan 90-120 days
17
Q
Haematocrit
A
- Percentage of blood volume occupied by erythrocytes
- Females - 42%
- Males - 47%
18
Q
Erythrocyte structure
A
- Made up of haemoglobin molecules - carry mostly O2 and some CO2
- Each erythrocyte has 280 million Hb molecules
- One Hb molecule - consists of 4 polypeptide chains (‘globin’)
- Each chain is bound to a pigment called ‘haem’ ⇢ contains iron
- Each haem group in Hb can carry an oxygen molecule
- Thus each Hb can carry up to 4 oxygen molecules
19
Q
Haemoglobin Structure - adult and foetal
A
Haemoglobin molecule is made up or 4 polypeptide chains
- Adult haemoglobin (HbA) - 2 alpha and 2 beta subunits
- Foetal haemoglobin (HbF) - 2 alpha and 2 gamma subunits
20
Q
Why is blood red?
A
- Interaction of iron and oxygen within haem units
21
Q
What nutrients are necessary for erythrocyte production?
A
- Vitamin B12
- Folate B9
- Iron
22
Q
What causes erythropoiesis?
A
- Hypoxia stimulates secretion of hormone ‘erythropoietin’ (EPO) in the kidneys ⇢ stimulates erythropoiesis in the bone marrow
- Causes - high altitude, blood loss, pregnancy
- During first weeks of life liver produces EPO. Liver is less sensitive to hypoxia than kidneys. Hence, premature newborns often have anaemia due to inadequate EPO.
23
Q
Haemolysis
A
- Destruction of erythrocytes to release haemoglobin into plasma
- About 1% of erythrocytes break down every day
- Macrophages (phagocytic cells) carry out haemolysis (found especially in spleen)
- Globin amino acids and iron are recycled
- Bilirubin - yellow coloured pigment formed from breakdown of haem, excreted in bile and urine
24
Q
What is haemoglobin?
A
A protein with 4 different protein (polypeptide) chains joined together
25
Bilirubin
* Formed from haem breakdown
* Prodominantly formed in spleen, bone marrow and liver
* Once formed, must be conjugated in the liver before being excreted in faeces (staining brown)
26
Erythrocyte lifecycle
27
What are the 2 major blood groups?
1. ABO
2. Rhesus
Blood group antigens are on surface of erythrocytes
28
Which blood group is universal donor?
Blood Group O-
29
Which blood group is universal recipient?
Blood Group AB+
30
Rhesus blood group
* Rhesus antigen - another surface antigen found on erythrocytes
* Inheritance via dominant gene - 85% of people are rhesus positive
* Anti-rhesus antibodies are produced in rhesus-negative person if come into contact with rhesus antigen in **pregnancy** or **blood transfusion**
* Pregnancy - if mother is Rh- and unborn baby inherits father's Rh+
* **‘Haemolytic disease** of the newborn’
* Injection of anti-Rh antibodies ('**D-antibodies**') inactivates foetal Rh antigens
31
Leukocytes
* Defend body from microbes (bacteria, viruses, fungi)
* 1% of blood
* contain nuclei (unlike erythrocytes)
32
2 types of leukocytes
1. Granulocytes - secretory granules in cytoplasm
2. Agranulocytes
33
3 types of Granulocytes
1. Neutrophils (60%)
2. Basophils (Mast Cells) (1%)
3. Eosinophils (2-4%)
34
Neutrophils
* Phagocytosis - ingest & destroy microbes
* Cells die ⇢ form pus
* Paramedics - first on scene
* Involved in: infection, tissue damage, leukaemia, RA, heavy smoking
35
Basophils (Mast Cells)
* In blood - basophils
* In tissues - mast cells
* Inflammation
* Release histamine and heparin from granules
* Histamine dilates blood vessels
* Not phagocytic
* (Increase blood area to site to deal with infection or injury)
* Involved in: inflammatory disease (i.e. inflammatory bowel disease), allergies, infections, hypothyroidism
36
Eosinophils
* Eliminate parasites (large ‘invaders’)
* Promote inflammation - allergic reactions
* Phagocytosis
* Involved in: parasitic infections, atopic (extrinsic) asthma, allergies
37
Agranulocytes
1. Monocytes/Macrophages (6%)
2. Lymphocytes (30%)
38
Monocytes / Macrophages
* Monocytes - in blood
* Macrophages - in tissue
* Function - inflammation and repair
* ‘Munch and present’
* **Phagocytosis** - ingest and destroy cellular debris and pathogens
* **Antigen presentation** - activate other immune cells
39
Lymphocytes
* **B-lympocytes** - antibody formation
* **T-lymphocytes** - kill invading pathogens
* **Natural (NK) cells** - kill invading pathogens
* Immunity against **specific** antigens
* **Immunological memory**
40
**Thrombocytes** (platelets)
* Small, **non-nucleated** discs
* Produced in **red bone marrow**
* **Megakaryoblasts ⇒** **megakaryocytes** ⇒ 1000s **thrombocytes**
* Produced with **thrombopoeitin** (hormone) in **liver**
* Lifespan - 10 days
* Blood clotting, platelet plug
41
What vasoconstrictor is activated by platelets?
Thromboxane - helps strengthen blood clot
42
4 stages of blood clotting
* **Vasoconstriction**
* Smooth muscle contracts
* **Collagen** exposed, **thromboxane** release ⇒ attracts **platelets**
* **Platelet plug formation**
* Platelets stick to damaged wall, activated and release proteins
* Platelet **aggregation**
* Platelets become sticky - **positive feedback loop**
* **Coagulation**
* Clotting factors form clot
* Enzyme ‘**thrombin**’ converts **fibrinogen** (protein) into **fibrin**
* Fibrin forms long sticky threads
* Erythrocytes get caught in web, clot forms
* **Fibrinolysis**
* Enzyme plasmin dissolves clot
43
Vitamin K
* Fat soluble vitamin
* Makes 4 clotting factors
* Found in dark green vegetables and tomatoes
* Vit K2 better absorbed, synthesised by intestinal bacteria and is in fermented foods
44
Anti-coagulents
* **Heparin** - produced in body by mast cells and basophils
* **Drugs** - Warfarin (blocks synthesis of clotting factors), Aspirin (suppresses thromboxane)
* **Anti-coagulent herbs** - ginkgo, garlic, giner, turmeric
* **Nutrients** - Vit E, essential fatty acids
45
2 types of blood cells
1. Myeloid - all blood cells except lymphocytes and natural killer cells original from myeloid line
2. Lymphoid
46
Key suffix definitions -
- blast
- cytosis
- penia
* -blast - immature cell
* -cytosis - more than normal cell numbers
* -penia - lack of cells
47
**Anaemia**
* Deficiency in haemoglobin
* Symptoms
* Fatigue
* Shortness of breath on exertion, palpitations, irritability, fainting
* Signs
* Tachycardia
* Thin, thready pulse
* Pallor
48
Haemoloytic Anaemias
Anaemia resulting from excessive breakdown of erythrocytes, when bone marrow activity cannot compensate for the loss of RBCs
* Causes
* Genetic (sick cell, thalassaemia)
* Rhesus factor incompatibility, malaria, drugs, chemical, autoimmune, radiation
* Signs/Symptoms
* Same as anaemia
* Jaundice (excess bilirubin production)
* Splenomegaly (large spleen, abdominal distension, feeling of fullness when eating)
* Gallstones
