week 6 Flashcards
Genes/ genetics, heart anatomy + heart physiology
What does DNA stand for?
DeoxyriboNucleic Acid
Where is it found?
in the nucleus, tightly packed
What is it made of?
nucleotides
DNA purpose
it is instructions to build proteins
Components of DNA
nucleus -> chromosomes -> nucleosome strands -> chromatin -> double helix ->
Parts of a chromosome
centromere, short arm, long arm, telomere
Telomere
Protect
Often reduce after each replication
Number of chromosomes
46 chromosomes
23 – Mum
23 – Dad
make 23 pairs
DNA letters (4)
Adenine
Cytosine
Guanine
Thymine
Types of chromosomes
22 - autosomes
1 - sex chromosome
Genotype
gene which codes for a specific trait
Phenotype
physical expression (appeartance)
Alleles - trait names
variation on the same trait
- if 2 identical ‐ called homozygous
- if 2 different ‐ called heterozygous
Alleles - trait types
dominant:
- appears more frequently than another trait
recessive:
- expressed only when genotype is homozygous
Polygenic
> 1 gene contributing
Monogenic
1 gene contributing
Mutation
change in nucleotide sequence
usually detected & repaired
Sex chromosomes
- females XX
- males XY (X from Mum, Y from Dad)
- X chromosomes larger -> more genes
Diploid
2n (2 x 23 = 46 chromosomes)
‘double’
Non gametes
Haploid
n (23 chromosomes)
‘single’
gametes
Cell division (2 types)
mitosis: division of somatic (body) cells
meiosis: division of gamete (sex) cells
• eggs and sperm
Mitosis
2 daughter cells
diploid
identical
asexual - for growth
Meiosis
4 daughter cells
haploid
non identical
sexual - make gametes
What is CVS and 3 components
cardiovascular system
heart
vessels
blood
Layers of the heart wall - Myocardial layers
Epicardium
Myocardium
Endocardium
What are the 4 cambers
right atrium
left atrium
right ventricle
left ventricle
What are the 4 valves
aortic valve
tricuspid valve
pulmonary valve
mitral valve
Coronary veins
superficial
empty into coronary sinus & right atrium
Major vessels (label to and from)
inferior vena carva superior vena carva pulmonary artery pulmonary vein arch of the aorta carotid artery thoracic aorta abdominal aorta jugular vein subclavian vein
Pressure
things move from high to low pressure
- volume decrease pressure increase (& visa versa)
- passive process
Cardiac muscle
muscle needs an electrical stimulus to make it work - heart has its own ‘stimulator’ - automaticity - cardiac conduction system
Sinoatrial (SA) node
the ‘pacemaker’
in the wall of the right atrium
Atrioventricular (AV) node
junction between atria and ventricles
AV bundle
in the septum
carries impulses to left and right bundle
branches
Purkinje fibres
distribute impulse through ventricles
ECG stands for
ElectroCardioGram
What does the ECG do?
measures electrical activity that accompanies
each heart beat
Components of ECG’s
P wave – atrial depolarisation
QRS complex – ventricular depolarisation
T wave – ventricular repolarisation
Cardiac cycle
period between start of one heartbeat and the
beginning of the next
includes both contraction and relaxation of both
atria and ventricles
Phases of cardiac cycle
atrial systole (contraction) atrial diastole (relaxation) ventricular systole (contraction) ventricular diastole (relaxation)
Cardiac cycle - rest
atrium pressure > ventricle
AV valves open
ventricle pressure < artery
• SL valves shut
Cardiac cycle - contraction (first and second sounds)
pressure in ventricle is higher than in atrium - AV valves shut to stop back flow
first heart sound (lubb) - can only occur once ventricle has begun contracting and its pressure rises
pressure in ventricle is higher than in
artery SL valves will open to let blood out
second heart sound (dubb) - can only occur once ventricle has begun to relax and its pressure drops
Heart sounds (list 4)
S1 – close AV valves
S2 – close SL valves
S3 as ventricle fills
S4 atrial systole
Average heart rate + cardiac cycle
80-100 BPM
0.8 seconds (0.5-relaxation, 0.3-contraction)
