Physiology And Human Health Flashcards
1
Q
Functions of the testes
A
- produce sperm in seminiferous tubules
* produce testosterone in interstitial cells
2
Q
_____ gland and seminal _____ secrete fluids that maintain _____ and ______ of sperm
A
- prostate
- vesticles
- mobility
- viability
3
Q
Seminiferous tubules unite to form ___ ___
A
Sperm duct
4
Q
What does semen contain?
A
- Sperm from the testes
- fructose from the seminal vesicles
- enzymes from the prostate gland to maintain the mobility and viability of sperm
5
Q
The male produces ____ (sperm cells) _______ from puberty until death and is said to display _____ ____[
A
- gametes
- continuously
- continuous fertility
6
Q
How is it possible for the male to display continuous fertility?
A
Because male sex hormone levels remain constant after puberty
7
Q
What and where are eggs formed from?
A
Eggs are formed from germline cells in the ovaries
8
Q
What do ovaries contain?
A
Immature ova (eggs) in various stages of development
9
Q
What is each ovum surrounded by?
A
A follicle that protects the developing ovum and secretes hormones
10
Q
Mature ova are released into the _____ where they may be fertilised by a sperm to form a _____
A
- oviduct
* zygote
11
Q
Describe the process of fertilisation
A
1) egg released from ovary
2) egg picked up by funnel of oviduct
3) egg moved along oviduct by hair- like cilia
4) sperm fertilised egg
12
Q
At puberty, what does the hypothalamus in the brain secrete?
A
A released hormone whose target is the pituitary gland
13
Q
What’s FSH?
A
Follicle-stimulating hormone
14
Q
What 2 hormones does the pituitary gland produce when stimulated at puberty?
A
• FSH
and
- ICSH in men
- LH in women
15
Q
What’s ICSH?
A
Interstitial cell-stimulating hormone
16
Q
What’s LH?
A
Luteinising hormone
17
Q
The release of hormones at puberty triggers the onset of ___ _____ in men and the _____ ____ in women
A
Sperm production
Menstrual cycle
18
Q
What are hormones classed as?
A
Chemical messengers
19
Q
What are hormones produced by?
A
Endocrine glands
20
Q
Where are hormones secreted?
A
Directly into the bloodstream
21
Q
When a hormone reaches a certain target tissue, what does it bring about?
A
A specific effect
22
Q
When FSH arrives in the male’s bloodstream, it promotes ____ _____ in the seminiferous tubules
A
Sperm production
23
Q
When ICSH arrives in the male’s bloodstream, it stimulates interstitial cells to produce the male sex hormone _____
A
Testosterone
24
Q
What’s the influence of testosterone?
A
- stimulates sperm production in seminiferous tubules
* activates prostate gland and seminal vesicles to produce their secretions
25
Describe the negative feedback control in the hormonal control of sperm production (simple)
* decreases in levels of FSH and ICSH
* decreases in testosterone levels
* increase in levels of FSH and ICSH
* increase in testosterone levels
26
Describe the negative feedback control in the hormonal control of sperm production (detailed)
* As testosterone concentration increases in the bloodstream, it reaches a level where it inhibits the secretion of FSH and ICSH by the pituitary gland
* This leads to a decrease in testosterone concentration
* Once testosterone levels fall below a set point, the inhibition is lifted and the pituitary gland secretes FSH and ICSH again
27
What are the two phases of the menstrual cycle?
* FOLLICULAR PHASE
| * LUTEAL PHASE
28
Purpose of FSH in the follicular phase of the menstrual cycle
* stimulates the development and maturation of each follicle
* stimulates the follicle to secrete oestrogen
29
Purpose of oestrogen in the follicular phase of the menstrual cycle
* stimulates proliferation of inner layer of uterus (endometrium) causing its repair following menstruation and preparing it for implantation
* affects consistency of cervical mucus enabling it to be more easily penetrated by sperm
* peak levels stimulate LH secretion by pituitary gland
30
What’s proliferation?
Cell division
31
What does the surge of LH trigger in the luteal phase of the menstrual cycle?
Ovulation
32
What does LH bring about the development of during the luteal phase of the menstrual cycle?
Development of the cuprous luteum from the follicle
Then stimulates the corpus luteum to secrete the sex hormone progesterone
33
What are oestrogen and progesterone known as?
The ovarian hormones
34
What does the progesterone released from the corpus luteum during the luteal phase of the menstrual cycle promote?
Promotes further development and vascularisation of endometrium into spongy layer rich in blood vessels, making it ready to receive a blastocyst if fertilisation occurs
35
What do peak levels of progesterone do in the luteal phase of the menstrual cycle?
* inhibits secretion of FSH and LH by the pituitary gland
| * concentrations of FSH and LH drop as a result and no new follicles develop at this time
36
What effect does the presence of fertilisation have on the luteal phase of the menstrual cycle?
If fertilisation does occur, the corpus luteum does not degenerate and progesterone levels remain high
37
What effect does the absence of fertilisation have on the luteal phase of the menstrual cycle?
* lack of LH leads, in turn, to degeneration of corpus luteum by ~day 22 in cycle
* This is followed by rapid drop in progesterone (and oestrogen)
* by day 28 these ovarian hormones are at such a low level that the endometrium can no longer be maintained and menstruation begins
* This involves the loss of the inner layer of the endometrium accompanied by a small volume of blood
38
Site of FSH production
Pituitary gland
39
One function of FSH in women
Stimulates the development and maturation of each follicle
40
Site of LH production
Pituitary gland
41
One function of LH
Brings about the development of the corpus luteum - stimulates ovulation
42
Site of oestrogen production
Ovary (released by developing follicle)
43
Functions of oestrogen
* stimulates repair of endometrium
| * stimulates secretion of LH by the pituitary gland
44
Site of progesterone production
Ovary ( released by corpus luteum)
45
One function of progesterone
Promotes further vascularisation of the endometrium
46
Describe the fertile periods in males
* the negative feedback of testosterone maintains a constant level of FSH and ICSH in blood
* This results in steady quantity of testosterone being secreted and sperm being produced, meaning men are continuously fertile
47
Describe the fertile period in females
* The interplay of pituitary and ovarian hormones in the body results in a period of cyclical fertility
* This is restricted to 1-2 days immediately following ovulation
48
Two ways to identify the fertile period in females
* temperature
| * mucus
49
Describe how temperature can be used to identify the fertile period in females
* Approx 1 day after LH surge triggering ovulation, woman’s body temp rises by ~ 0.5*C under the action of progesterone
* The infertile phase is resumed, on avg, after the 3rd daily recording of the higher temp by which time the unfertilised egg had disintegrated
50
Describe how mucus can be used to identify the fertile period in females
* cervical mucus secreted into vagina during fertile period is thin and watery to allow sperm easy access to female reproductive system
* After ovulation the mucus gradually increases in viscosity under the action of progesterone showing that the system had returned to infertile phase
51
Failure of the pituitary gland to secrete adequate FSH or LH may lead to a failure in _____
Ovulation
52
Ovulation can be successfully stimulated by?
* drugs that mimic the normal action of FSH and LH
* Drugs that prevent the negative feedback effect of oestrogen on FSH secretion during the Luteal phase of the menstrual cycle
53
Drugs that stimulate ovulation are so effective they can do what?
Can bring about multiple ovulation which can lead to multiple births or can be used to collect ova (eggs) for IVF programmes
54
What’s insemination?
The introduction of semen into the female reproductive tract
55
What’s artificial insemintion?
The insertion of semen into the female tract by some means other than sexual intercourse
56
When may artificial insemination be used?
* man has low sperm count
| * donor sperm when partner is sterile
57
Describe artificial insemination
* if a man has a low sperm count, several samples of his semen can be collected over a period of time and preserved by freezing until required
* They are then defrosted and released together (concentrated) into the partner’s reproductive tract at the time when she is most likely to be fertile
58
When can intracytoplasmic sperm injection be employed?
When the man has a very low sperm count or many of his mature sperm are defective in some way
59
What does intracytoplasmic sperm injection (ICSI) involve?
Drawing the head of a healthy sperm into a syringe needle and injecting it directing into an egg to bring about fertilisation.
The egg is held with a holding tool
60
What does IVF attempt to solve?
The problem of infertility caused by a blockage of the oviducts
61
What does IVF enable?
Enables fertilisation to occur outside the bodies of the potential parents in a culture dish (in vitro)
62
Describe In Vitro Fertilisation (IVF)
1) Woman given hormonal treatment to stimulate multiple ovulation
2) Eggs surgically removed - alternatively a sperm may be injected directly into an egg at this stage (ICSI)
3) Eggs are mixed with sperm and nutrients in a culture dish to allow fertilisation
4) Zygotes are incubated until they have formed at least 8 cells
5) 2/3 embryos inserted into mothers uterus for implantation
6) Remaining embryos are frozen
63
What can PGS and PGD be used in conjunction with?
IVF to identify abnormalities
64
What is Preimplantation genetic screening (PGS)
PGS is a non-specific approach that checks the embryo for single gene disorders and common chromosomal abnormalities in general
65
What’s Preimplantation genetic diagnosis (PGD)?
a specific approach that is used to check for a known chromosomal or gene defect
66
What do PGS and PGD enable?
These tests enable experts to select which embryos should and which should not be allowed to become implanted in the mothers endometrium
67
What’s contraception?
Contraception is the intention prevention of conception or pregnancy by natural or artificial means
68
What are barrier methods of contraception?
* A barrier method makes use of a device that physically blocks the ability of sperm to reach an ovum
* These methods are v effective but not as successful as chemical methods
* Male/female condoms, diaphragm, cervical cap
69
What are male/female condoms?
A rubber sheath that fits over the man’s penis or covers the inside of the vagina
Both collect semen following ejaculation, preventing sperm reaching the uterus
70
What’s a diaphragm?
A dome shaped rubber cap that is inserted into the woman’s vagina to block the cervix before sexual intercourse
71
What’s a cervical cap?
A rubber structure that fits tightly around the cervix and can be left in position for a few days
72
What’s an intra-uterine device (IUD)?
A T-shaped structure that is fitted into the uterus for many months or years to prevent the implantation of an embryo into the endometrium
73
Describe the combined pill
These oral contraceptive pills normally contain synthetic progesterone and oestrogen
A pill is taken every day for 3 weeks from the final day of the previous menstrual period
High concentrations of progesterone and oestrogen exert -ve feedback control inhibiting FSH and LH secretion by the pituitary gland
As little or no FSH is present, follicle maturation remains inhibited and decreases levels of LH prevent ovulation
Dummy (placebo) pills are usually taken during the 4th week to allow the levels of oestrogen and progesterone to drop and menstruation to occur
74
Describe sterilisation procedures in males
In men vasectomy involves the cutting and trying of the two sperm ducts to prevent the release of sperm
75
Describe sterilisation procedures in women
In women tubal ligation involves the cutting and tying of the two oviducts to prevent eggs meeting sperm and reaching the uterus.
This is highly effective and irreversible
76
Describe the negative feedback control involving ovarian hormones
High concentrations of progesterone and oestrogen exert negative feedback control inhibiting FSH and LH secretion by the pituitary gland.
77
Describe ‘mini pills’
These are known as progesterone only pills because they contain synthetic progesterone but no oestrogen
They work by causing the thickening of cervical mucus which reduced the liability of sperm and their access to the uterus.
78
Describe morning after pills
Aka emergency contraceptive pills
They often contain higher doses of the hormones (P+Oe) found in standard oral contraceptive pills
They are taken by the woman after unprotected sexual intercourse to prevent ovulation or implantation if fertilisation has taken place unintentionally.
Ideally the pills should be taken as soon as possible after unprotected sex but it may be effective up to 72 hrs afterwards
79
What’s antenatal screening?
During pregnancy women undergo a variety of tests and procedures to monitor the health of themselves and the foetus.
Identifying risk of disorder so further tests and a potential diagnosis can be offered.
```
The standard tests include:
• a physical examination
• check medical history for possible complications
• blood pressure
• blood type + urine samples
```
80
What’s ultrasound imaging?
A scanner picks up high frequency sounds which bounce off the foetus and converts these to ultrasound images on a computer screen.
Two routine scans are carried out - dating scan and anomaly scan
81
Describe the dating ultrasound scan
* carries out between 8-14 weeks
| * tests for chemical markers are used to determine the stage of the pregnancy and calculate the due date
82
Describe the anomaly ultrasound scan
* performed at 18-20 weeks when the foetus is longer
| * check for any serious physical development abnormalities
83
Describe biochemical tests (pregnancy)
Biochemical tests are used throughout the pregnancy to ensure that the normal course of events is taking place.
With consent the mothers blood type is identified and regular blood and urine tests are carried out through pregnancy to monitor the concentrations of mother themselves eg HCG detection in the blood and urine is the basis of early pregnancy tests.
Tests for chemical markers
84
Describe the biochemical test for AFP
* 16-18 weeks
* woman offered test to check for AFP (alpha-feto protein concentration increases in the mothers bloods while pregnant)
* low levels of AFP (<0.5) (0.5-2.49 is normal) are found in cases such as Down Syndrome
* The result of this test in conjunction with the mothers age allow experts to asses the risk of chromosomal abnormalities present in the foetus.
85
Why is the timing of biochemical tests very important?
If carried out at the wrong time they can produce false positive or false negative results due to the natural changes in marker concentrations throughout the pregnancy
86
Why would a test of HCG concentration be meaningless at 10 weeks ( the elrory time)
In a normal pregnancy HCG concentration increased during weeks 6-10 and then decreases.
HCG conc. remains Hugh when the foetus has Down’s Syndrome.
A test at 10 weeks would lead to a false positive result ( test shows foetus has the condition when it does not)
87
What is diagnosis testing?
A definitive test used to establish whether or not a person is suffering from a specific condition or disorder
88
What’s a screening test?
A more general test not looking for a specific disorder
89
Why are diagnosis tests offered to pregnant women?
If:
• evidence of potential problems had emerged from screening tests
* there is a history of genetic disorders in the family
* she is in a high risk category eg over the age of 35
90
What are karyotypes generated from?
Diagnosis tests use foetal material taken from the mother during the pregnancy to generate a karyotype of the foetus
91
What is a karyotype?
A karyotype is a visual display of an individuals complete chromosome complement arranged in homologous pairs.
These tests have an associated risk of causing a miscarriage but have a very low error rate
92
What’s the name of the process where a sample of fluid is extracted from the mothers uterus to generate a karyotype?
Amniocentesis procedure
93
How is a karyotype generated?
The cells removed by the amniocentesis procedure are cultured, stained and examined under the microscope.
A full chromosome compliment is photographed and the chromosomes arranged into pairs to form the karyotype.
Results take about 2 weeks and allow the diagnosis of a range of conditions
Eg a karyotype containing an extra copy of chromosome 21 indicates Down Syndrome
94
What’s chronic villus sampling?
CVS takes a sample of placental cells using a tube inserted into the reproductive tract.
Can be carried out as early as 8 weeks into the pregnancy
The cells are cultured and karyotyped as before.
The prospect of termination at this earlier stage may be less traumatic for parents that the incidence of miscarriage is higher at 2%
95
What are autosomes?
All other chromosomes in the genotype other than the sex chromosomes
96
What genes does autosomal recessive inheritance affect?
The affected gene is on an autosome and is a recessive allele
97
Patterns of autosomal recessive inheritance
* rarely expressed in the phenotype
* skips generations
* males + females approx equally affected
* all sufferers are homozygous recessive
* non sufferers are homozygous dominant or heterozygous
98
Example of autosomal recessive inheritance
Cystic fibrosis
99
What genes are affected by autosomal dominant inheritance?
The affected gene is on an autosome and is a dominant allele
100
Autosomal dominant patterns of inheritance
* the trait appears in every generation
* all sufferers have an affected parent
* males + females equally affected
* all non sufferers are homozygous recessive
* sufferers are either homozygous dominant or heterozygous
101
Example of autosomal dominant inheritance
Huntington’s Disease
102
Autosomal incomplete dominance pattern of inheritance
* the fully expressed form of condition occurs rarely
* each sufferer of fully expressed form has 2 parent who have the partly expressed form
* the partly expressed form occurs more frequently
* males + females affected equally
103
Example of autosomal incomplete dominance
Sickle cell anaemia
104
What are sex linked genes?
Many genes of the females second X chromosome which are absent from the males Y
105
Pattern of inheritance when the affected gene is on the X chromosome and is a recessive allele
* more males affected
* no sons of affected males would show the trait
* some grandsons of an affected male would show the trait
106
Example of sex linked recessive inheritance
Haemophilia
107
What does the heel prick test screen newborn babies for?
PKU
Hyperthyroidism
CF
Galactosaemia
108
What is PKU caused by?
A substation mutation which results in a genetic error in metabolism
The enzyme which converts phenylalanine to tyrosine if non functional
109
How are PKU patients treated?
Treating PKU patients with a phenylalanine restricted diet prevents irreversible damage to mental development.
110
What’s the cardiovascular system composed of?
* blood
* blood vessels
* the heart which circulated blood around the system
111
What’s the pulmonary system?
Circulated blood from heart to lungs and back to heart
112
What’s the systemic system?
Circulates blood from the heart to the body and back
113
What’s the hepatic portal vein?
Carried blood from intestines to liver
114
What do blood vessels do?
Transport blood around the body
115
What’s the lumen of a blood vessel lined with?
A thin layer of epithelial cells called the endothelium
116
What does blood consist of?
Red blood cells
White blood cells
Platelets bathed in plasma
117
What is plasma?
A watery, yellowy fluid that contains many dissolved substances such as glucose, amino acids, respiratory gases, plasma proteins and useful ions
118
Where do arteries carry blood?
Away from the heart
119
Blood in the arteries is at ____ pressure
High
120
What do arteries consist of?
Arteries have an outer layer of connective tissue containing elastic fibres and a thick middle layer containing smooth muscle with more elastic fibres
121
What do the elastic fibres in arteries enable?
Enable the walls of the arteries to stretch and recoil accommodating the surge of blood after each heart contraction
122
What does the the thick muscle layer of an artery allow?
Allows the artery to withstand the high pressure produced
123
What do arteries branch off into?
Smaller arterioles
124
What’s vasoconstriction and vasodilation?
The smoothie muscle in the walls of arterioles can contract or relax to control blood flow depending on the body’s requirements
125
Example of vasoconstriction and vasodilation
During strenuous exercise arterioles leading to working muscles undergo vasodilation.
At the same time the arterioles leading to the small intensity undergo vasoconstriction, reducing blood flows to these parts
126
What are capillaries?
Capillaries are microscopic exchange vessels with all exchanges of substances between blood and living tissues taking place through their thin walls
127
What are capillaries composed of?
Endothelium
| Only one cell thick
128
Describe blood flow through the blood vessels
Heart -> arteries -> arterioles -> capillaries -> ventless -> veins
129
Where do veins carry blood?
Back to the heart
130
What are veins composed of?
They have an outer layer of connective tissue containing elastic fibres
The muscular layer and layers of elastic fibres are thinner than those in an artery because blood flows at lower pressure.
Valves
131
Why do veins contain valves?
To prevent the back flow of blood
132
How does tissue fluid differ from plasma?
It contains no plasma proteins
133
Why does tissue fluid not contain plasma proteins?
Protein molecules are too large to be filtered through the capillary wall
134
How are gases exchanged between tissue fluid and cells?
Tissue fluid contains a high concentration of glucose, dissolved oxygen etc
These substances diffuse down a concentration gradient into nearby cells, supplying their requirements.
At the same time, carbon dioxide and other metabolic wastes diffuse out of the cells into the tissue fluid for excretion
135
Where does most of the tissue fluid return to the blood?
In the capillaries at the venous end of the capillary bed
136
What is excess tissue fluid absorbed by?
Thin walled lymphatic vessels
137
Once in a lymphatic vessel what is tissue fluid called?
Lymph
138
Describe lymphatic system
Lymph is collected by a vast network of tiny vessels which unite to form larger vessels
Lymphatic vessels return the lymph to circulatory system where it’s eventually passed onto cardiovascular system through two lymphatic ducts at the subclavian veins at each arm
139
Why is the lymphatic system regarded as a specialised part of the cardiovascular system?
As it consists of:
* lymph fluid derived from blood
* system of vessels that returns lymph to blood
140
What is the flow of lymph enabled by?
Enabled by compression when muscles contract during breathing and body movements
141
What is the back flow of lymph prevented by?
Valves in the larger vessels
142
Which side of the heart is the tricuspid valve on?
Right
Tri before you bi
143
What side of the heart is the bicuspid valve on?
The left
Tri before you buy
144
Describe blood flow through the heart
Body-> vena cava -> right atrium -> tricuspid valve -> right ventricle -> semi-lunar valve -> pulmonary artery -> lungs
Lungs-> pulmonary vein -> left atrium -> bicuspid valve -> left ventricle -> semi-lunar valve -> aorta -> body
145
What’s heart rate?
Pulse - no.of heartbeats/ minute
146
What’s stroke volume?
Vol. of blood expelled by each ventricle on contraction
147
What’s cardiac output?
Vol. of blood pumped through each ventricle/ minute
148
Formula for cardiac output?
Heart rate x Stroke volume
149
How would u increase cardiac output?
```
Increase stroke volume
or
Increase heart rate
or
Increase both
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150
What’s the average length of the cardiac cycle?
0.8s based on a heart rate of 75bpm
151
What’s the cardiac cycle?
The pattern of contraction (systole) and relaxation (diastole) shown by the heart during one complete heartbeat
152
What are the 4 stages of the cardiac cycle?
1) Diastole (relax)
2) Atrial systole (contraction)
3) Ventricular systole (contraction)
4) Diastole (relax)
153
Describe the first diastole of the cardiac cycle
* during diastole the return of blood (via the vena cava and pulmonary artery) to the atria causes the volume of blood and the pressure in the atria to increase
* when atrial pressure exceeds that in the ventricles the AV valves are pushed open and blood starts to enter the ventricles
154
Describe the atrial systole (contraction) of the cardiac cycle
* During atrial systole the two atria contract simultaneously and send the remaining blood down into the ventricles through the open AV valves
* the ventricles full up with blood
* the semi lunar valves remain closed
155
Describe ventricular systole (contraction) of the cardiac cycle
* The AV valves close
* The pressure exerted on the blood in the ventricles (as the cardiac muscle contracts) soon exceeds the blood pressure in the arteries
* The SL valves are pushed open
* Blood is pumped out of the ventricles, through the SL valves and into the aorta and pulmonary arteries
156
Describe the second diastole of the cardiac cycle
• during diastole the higher pressure of blood in the arteries closed the SL valves again and the next cardiac cycle begins
157
What is responsible for the heart sounds heard with a stethoscope?
The opening and closing of the AV and SL valves
158
The heartbeat originates in the heart but is regulated by what?
Both nervous and hormonal control
159
The sequence of events that occur during each heartbeat is brought about by the activity of the ________ and the _____ _____ of the heart
Pacemaker
Conducting system
160
What is the pacemaker know as?
The sino-atrial node (SAN)
161
Where is the sino-atrial node (SAN) located?
In the wall of the right atrium
162
What sets the rate at which the heart contracts at?
The auto-rhythmic cells in the SAN
163
How do the auto-rhythmic cells in the SAN set the rate at which the heart contracts at?
By initiating electrical impulses that make cardiac muscle cells contract
164
What regulates the rate of the SAN and how?
The medulla regulates the rate of the SAN through the antagonistic action of the autonomic nervous system
165
What’s the autonomic nervous system (ANS)?
This is the part of the nervous system responsible for control of those bodily functions which are not consciously directed
Eg breathing, heartbeat + digestive processes
166
Describe how the cardiac conducting system works
* the timing of the cardiac muscle cell contraction is controlled by impulses from SAN spreading through the atria causing atrial systole
* the impulse is picked up by the AVN (located in the centre of the heart)
* Impulses from the AVN travel down the conducting fibres in the central wall of the heart which divide into left and right branches
* Each branch is continuous with a network of tiny fibres in the ventricle walls and stimulation causes ventricular systole from the apex upwards
167
How does the cardio-accelerator centre send it’s never impulses and what does it result in?
Via a sympathetic nerve to the heart
Increase in heart rate
168
How does the cardio-inhibitor centre send its information and what does it result in?
Via a parasympathetic nerve
Decrease in heart rate
169
What is the actual rate at which the heart beats determined by?
Which system (cardio accelerator centre/ cardio inhibitor centre) exerts the greater influence over the heart at any given moment
170
What does an electrocardiogram (ECG) detect?
Tiny currents generated by the electrical activity of the heart
171
What is the P wave of an ECG?
Wave of electrical excitation spreading across the atria from the SAN- atrial systole
172
What is the QRS complex of an ECG?
Wave of excitation passing through the ventricles - ventricular systole
173
What’s the T wave of an ECG?
Electrical recovery of the ventricles - diastole
174
What are the two branches of the autonomic nervous system?
Sympathetic
Parasympathetic
175
What does the sympathetic nerve of the ANS do?
Releases noradrenaline which increases heart rate
176
What does the parasympathetic nerve of the ANS do?
Releases acetylcholine which decreases heart rate
177
What is blood pressure?
The force exerted by blood against the walls of the blood vessels
178
What’s blood pressure measured in?
Millimetres of Mercury (mmHg)
179
What’s blood pressure generated by
The contraction of the ventricles
180
Where is blood pressure at its highest?
The large elastic arteries (aorta and pulmonary artery)
181
During ____ ____ the pressure of blood rises to a maximum (____mmHg)
Ventricular systole
120
182
During ____ ____ blood pressure drops to a minimum (__mmHg)
Ventricular diastole
80
183
Why is there a progressive decrease in blood pressure as it travels round the circulatory system?
Due to friction between the blood and the vessel wall and resistance from the vessel walls to blood flow
184
How can systolic and diastolic pressure be measured?
Using a sphygmomanometer in mmHg
185
What is a typical blood pressure reading for an adult?
120/80 mmHg
186
Describe how blood pressure is measure using a sphygmomanometer
* the cuff is inflated until the pressure drops blood flowing through the artery
* the inflatable cuff deflated gradually
* the blood starts to flow (detected by a pulse) of systolic pressures
* the blood flows freely through the artery (and a pulse is not detected) at diastolic pressure
187
What is hypertension?
High blood pressure
188
What does high blood pressure result in?
The prolonged elevation of blood pressure at rest
189
What is hypertension indicated by?
Systolic values >140mmHg and diastolic values >90mmHg
190
What is hypertension a major risk factor for?
Many diseases including coronary heart disease and stroke
191
Hypertension can be found in people with an unhealthy lifestyles that includes:
* being overweight
* not taking enough exercise
* smoking
* a diet high in fatty foods
* consuming too much salt
* regularly drinking alcohol to excess
* being under continuous stress
192
What is the process of atherosclerosis?
The accumulation of fatty material (consisting mainly of cholesterol), fibrous material, and calcium forming an atheroma or plaque beneath the endothelium
193
What happens as the atheroma grows?
The artery thickens and loses it’s elasticity
The diameter of the artery becomes reduced and blood flow becomes restricted resulting in an increased blood pressure
194
Atherosclerosis is the root cause of various cardio vascular diseases including?
Angina
Heart attack
Stroke
Peripheral vascular disease
195
What do the coronary arteries do?
Supply the heart muscle with oxygen and nutrients
196
Restriction/ blockage of the coronary blood supply results in what?
Angina - crushing chest pain radiating down left arm and up to the neck and jaw
197
What can complete occlusion (blockage) of the coronary arteries cause?
A heart attack (myocardial infraction if left untreated)
198
What is blood clotting?
A protective device triggered by damage to cells to prevent blood loss from a wound
199
When may thrombosis be triggered?
When an arithmetic ruptured damaging the endothelium
200
What’s thrombosis?
The formation of a clot (thrombus)
201
What does thrombin (active enzyme) produce?
Fibrinogen (soluble)
And
Fibrin (insoluble)
202
What do fibrin threads do?
Become interwoven into a framework to which platelets adhere, forming a blood clot
203
What is a thrombus?
A blood clot
204
What does thrombosis restrict?
Further restricts blood flow in addition to that cause by atheromas
205
If a thombus breaks loose what is it referred to?
An embolus
206
What does an embolus do?
It travels through the bloodstreams until it blocks a smaller blood vessel causing blood flow to be severely restricted or halted
207
A thrombosis in a coronary artery can lead to what?
A heart attack (myocardial infarction- MI)
208
A thrombosis in an artery in the brain can lead to what?
A stroke
209
What happens to cells when thrombosis occurs?
Cells are deprived of oxygen leading to the death of tissues
210
What is peripheral vascular disease?
Narrowing of the arteries due to atherosclerosis of arteries other than those of the heart or brain
211
Which arteries are most commonly affected by peripheral vascular disease?
The arteries to the legs
212
What is a deep vein thrombosis?
A DVT is a blood clot (thrombus) that forms in a deep vein in the lower leg, causing the affected area to swell and become painful
213
What’s a pulmonary embolism?
When a clot from a deep vein breaks free and is transported via the vent cava and heart chambers to the pulmonary artery where it may block a small arterial branch
214
What’s the treatment for pulmonary embolism?
Anti-coagulant drugs (heparin) or in severe causes thrombolytic drugs (streptokinase) to dissolve the clot
215
What is cholesterol?
A lipid (fat)
A component of cell membranes and is used to make hormones eg the sex hormones testosterone, oestrogen, and progesterone
216
A diet high in _____ ___ or ______ causes an increase in blood cholesterol levels
Saturated fats
Cholesterol
217
Foods that include saturated fats and cholesterol?
Animal fat eg cheese, eggs, beef, pork, poultry
218
What are lipoproteins?
Molecules containing a combination of lipid and protein and are found in the blood plasma
219
What’s the role of lipoproteins?
To transport cholesterol from one part of the body to another
220
What are Low-density lipoproteins?
Produced in liver
Transport cholesterol to body cells that need it
221
What do LDL receptors do?
Attach to LDL cholesterol and engulf it in to the cell where it releases the cholesterol for use
222
What happens once a body cell has sufficient cholesterol?
* A negative feedback system is triggered
* This inhibits the synthesis of new LDL receptors
* Less LDL cholesterol can be absorbed from the blood by body cells resulting in deposits forming on arterial walls producing an atheroma
223
What do High Density Lipoproteins do? (HDL)
Made in liver
Transport excess cholesterol from body cells back to the liver for elimination of preventing the accumulation of cholesterol in the blood
224
HDL cholesterol is not taken into ____ ____ and does not contribute to _______
Artery walls
Atherosclerosis
225
What will a higher ratio of HDL to LDL result in?
Lower blood cholesterol and a reduced chance of atherosclerosis
226
Regular physical activity tends to ___ HDL levels
Raise
227
How do drugs such as statin reduce blood cholesterol?
By inhibiting an enzyme essential for the synthesis of cholesterol by liver cells
228
As more cholesterol originated from manufacture in the liver than from the diet, a ___ in cholesterol production by the liver soon results in a drop in ___ ______ level
Drop
Blood cholesterol
229
Statin also increases the no. of __ ____ which bring about a reduction in the level of __ ______ in the blood
LDL receptors
LDL cholesterol
230
What does chronic elevation of blood glucose levels lead to?
The endothelium cells taking in more glucose than normal, damaging the blood vessels
231
What may atherosclerosis developing lead to?
Cardio vascular stroke
Peripheral vascular disease
232
What may small hard vessels (arterioles and venues) damaged by elevated glucose levels result in?
Haemorrhage of blood vessels in the retina, renal failure or peripheral nerve disfunction
233
What happens in vascular disease
* endothelial cells lining arterioles become thicker and weaker
* walls lose their strength and may burst and bleed into surrounding tissues, reducing blood flow through the body reducing blood supply
234
Describe vascular disease in the retina
Diabetic retinopathy from prolonged high blood pressure causes small vessels in the eye to haemorrhage
Left untreated it can cause blindness
235
Describe vascular disease in the kidneys
Damage to arterioles can cause renal failure as kidneys are no longer able to effectively filter and purify blood leading to...
* ankle swelling
* dark urine containing blood
* shortness of breath on exercise
236
Describe vascular disease in peripheral nerves
Peripheral neuropathy neves are damaged due to prolonged exposure to high glucose levels and can take form of numbing, tingling, or pain in the hands, arms, toes + feet
If left untreated can lead to development of ulcers + eventually amputation
237
Glucose is need as a _____ ____ by all living cells
Respiratory substrate
238
To generate a regular supply of glucose present in the bloodstream, the body employs a system of ____ ____ ____
Negative feedback control
239
What cells detect a rise in blood glucose concentration (following a meal)?
Receptor cells only the pancreas
240
What do receptor cells in the pancreas produce?
Insulin or glucagon
241
What does insulin do?
Activates the conversion of glucose to glycogen in the liver decreasing blood glucose concentration
242
What cells detect a drop in blood glucose concentration (following fasting)
Receptor cells in the pancreas
243
What does glucagon do?
Activated the conversion of glycogen to glucose in the liver increasing blood glucose concentration
244
Insulin and glucagon act ________
What does this mean?
Antagonistically
This means they counteract each other/ act against each other
245
During exercise or fight/flight responses the body requires what?
Additional supplies of glucose to quickly provide energy
246
During exercise or fight/flight responses how are glucose concentrations in the blood raised?
By adrenaline released from the adrenal glands
247
What releases adrenaline?
The adrenal glands
248
What does adrenaline do?
It overrides normal homeostatic control inhibiting the secretion of insulin and promoting the secretion of glucagon thereby increasing blood glucose concentration
249
When does type 1 diabetes occur?
In childhood
250
What is type 1 diabetes?
Cells have the normal number of insulin receptor cells but the pancreas is unable to produce insulin
251
How can type 1 diabetes be treated?
Regular injections of insulin
252
When does type 2 diabetes occur?
Develops later in life
Sufferers are usually overweight or obese
253
What is type 2 diabetes?
The pancreas produces insulin but body cells are less sensitive to it
This insulin resistance is linked to a decrease in the number of insulin receptors in the liver, leading to a failure to convert glucose to glycogen
254
How can be type 2 diabetes be treated?
By diet control, exercise and weight loss
255
In both types of diabetes, blood glucose concentrations will ___ _____ after a meal
Rise rapidly
256
In both types of diabetes, what happens when blood glucose concentrations rise rapidly after a meal?
The kidneys are unable to cope and kidney filtrate is so rich in glucose that it is not absorbed back into the blood and is excreted in urine.
257
What is often used as an indicator for diabetes?
Testing urine for the presence of glucose
258
Describe a glucose tolerance test
This is a clinical test used to diagnose diabetes
The blood glucose concentrations of an individual are measured after fasting
They consume a known mass of glucose and changes in their blood glucose concentrations are monitored for at least the next 2 hrs
The results are plotted to give a glucose tolerance curve
259
What’s obesity?
Obesity is characterised by an accumulation of excess body fat in relation to lean body tissue (muscle)
260
Why is obesity a major risk factor for?
Cardiovascular disease
Type 2 diabetes
261
What’s the most common cause of obesity?
Excessive consumption of food rich in fats and free sugars combined with lack of physical activity
262
How is body mass index (BMI) calculated?
Body mass (kg)
———————-
Height (m)^2
263
A BMI greater than __ is used to indicate obesity
30
264
What is a skin fold calliper?
Used to measure the thickness of a fold of skin containing a layer of subcutaneous fat at 4 specific sites in the body
265
___ shaped people with excess _____ fat are known to be at a greater risk of CVD and type 2 diabetes than ____ shapes people with excess fat around their ___
Apple
Abdominal
Pear
Hips
266
Women are considered to be at risk when the waist/hip ratio is > ___
0.8
267
Men are considered to be at risk when the waist/hip ratio is > ___
1.0
268
Obesity is linked to what?
High fat diets
+
A decrease in physical activity
269
The energy intake in the diet should limit ___ and ___ ____ as fats have a high _____ value per gram and free sugars require no _____ ____ to be expended in their digestion
Fats
Free sugars
Calorific
Metabolic energy
270
What are some risk factors of CVD?
* physical inactivity
* Diabetes
* Obesity
* Excess alcohol
* Smoking
* Diet high in saturated fat
* High blood pressure
* Stressful lifestyle
* High LDL-cholesterol
271
Exercise increases ___ ______ and preserves ___ tissue
Energy expenditure
Lean
272
How can exercise help reduce risk factors for CVD?
* keeping weight under control
* minimising stress
* reducing hypertension
* improving blood lipids profiles (raises HDL)
273
Describe the results of a glucose tolerance test on a non diabetic
Rise to max around 30 mins, quickly drops to initial level within 2.5 hrs. Insulin production is normal
274
Describe the glucose tolerance test results for mild diabetes
Normal fasting level, rises to a max around 60 mins before decreasing. Delay in insulin response indicates mild diabetes. Diet controlled.
275
Describe the glucose tolerance test results for severe diabetes
After fasting, glucose still abnormally high and continued to rise. Indicates severe diabetes - little or no insulin produced.
