Transcript B - ME School of Excellence

B5 Summary
Inside or Outside
• Endo skeleton – internal skeleton made
from cartilage (shark) or bone (human)
e.g. humans, frogs, birds. These are
living tissues.
• Exo skeleton – external skeleton made
from chitin e.g. insects
• Some animals e.g. worms do not have a
skeleton made of hard material
Skull
Clavicle
Scapula
Sternum
Rib
Humerus
Vertebral Column
Ulna
Radius
Carpals
Metacarpals
Pelvis
Phalanges
Femur
Patella
Tarsals
Tibia
Metatarsals
Phalanges
Fibula
Long Bones
• Long Bones are hollow
– this makes them
stronger than solid
bones
• The head is covered
with cartilage
• The shaft is filled
with bone marrow
with blood vessels
Bones
• Cartilage and bone are susceptible to
infection but can grow and repair
themselves
• In humans, the skeleton starts off being
cartilage which is slowly replaced by the
addition of calcium and phosphorous
(ossification)
• The more cartilage in a bone = the
younger the person
Fractures
Fractures
• Elderly people are more prone to fractures
due to soft bones (osteoporosis)
• If you move someone with a fracture you
can damage blood vessels and nerves.
• You should never move someone with a
suspected spinal fracture without special
first aid training.
Ball & Socket Joint and Hinge Joint
Joints
• Hip and knee joints can be replaced
(danger of rejection and infection)
• Ligaments connect bone to bone (helps
to prevent dislocations)
• Tendons connects muscle to bone
• Cartilage absorb shock
• Synovial fluid absorbs shock and acts as
a lubricant
to head
and body
to lungs
aorta
pulmonary
artery
from head
and body
semi-lunar
valve
pulmonary
vein
vena cava
from lungs
right
atrium
left
atrium
bicuspid valve
tricuspid valve
Arteries = high
pressure
Veins = low
pressure
right
ventricle
valve tendons
left
ventricle
muscle
Circulatory Systems
• No Circulation
– Some animals are so small e.g. amoeba that
they do not have a blood circulatory system
• Open and Closed
– Insects have an open CS, humans have a
closed CS e.g. blood flows in BV
• Single Circulation
– One circuit from a 2 chambered heart
• Double Circulation
– Two circuits from a 4 chambered heart
The History of Blood Circulation
• Galen, 200AD
• First doctor to realise
the importance of the
pulse in medicine
• He believed the liver
made blood
• And the heart pumped
blood around the body in
a backwards and
forwards motion
The History of Blood Circulation
• William Harvey, 1628
• He explained the heart
had 4 chambers and
that blood travelled
through arteries and
veins
• He believed they were
joined by tiny blood
vessels but no
microscope was good
enough to see
capillaries.
The Cardiac Cycle
• Takes about 0.8 seconds
• Systole = contraction, diastole = relaxation
The Cardiac Cycle
Heart relaxes and
blood enters both
atria
Ventricles contract from
the bottom upwards
which forces blood into
the pulmonary artery or
aorta
Atria contract at the
same time which
forces blood into both
ventricles
Pacemaker Cells
• The Sino-Atrial Node
(SAN) generates
electrical impulses
• They spread across
the atria causing
them to contract
Pacemaker Cells
• The impulse reaches the
Atrio-Ventricular Node
(AVN)
• Impulses spread across
the ventricles
• They contract from the
bottom upwards
• Impulses from the vagus
and sympathetic nerve
can modify the
heartbeat
Electrocardiogram
• An ECG shows the change in electrical
impulses in the heart muscles
• The video of an echocardiogram shows if any
parts of the heart, such as valves are not
working properly.
P waves
(impulses
from SAN)
R waves
(impulses in
ventricles)
T waves (as
ventricles
contract)
Heart-Assist Devices
• Doctors use ‘heart-assist’ devices to
reduce the work done by heart muscles.
• They help to pump the blood.
• This allows the heart muscles to
recover and then the device can be
removed.
• Weak or damaged valves can also be
replaced by artificial valves.
Heart Health
• Many factors can contribute to a poor
circulatory system:
– Fatty diets – can lead to cholesterol
– Smoking – reduce amount of oxygen available
– Stress – high blood pressure
– Inhaling solvents – can lead to heart attack
– Injecting drugs – bacterial infections
– Alcohol – lower BP, raise fat levels in blood
Blood Groups (Grade A)
• Before a blood transfusion is carried out, the
new blood is checked to ensure it does not
react with the patient’s blood
• Early attempts at blood transfusion were not
successful
• Mixing blood from 2 people often caused
blood clumping (agglutination)
• Karl Landsteiner (1901) solved this by
discovering the four blood groups.
Blood Groups (Grade A)
• The groups depends on the presence or
absence of agglutinins that consist of:
– 2 proteins, antigen A or antigen B on the surface
of red blood cells
– 2 antibodies, anit-A or anti-B in blood plasma
• Anti-A causes RBC containing antigen A to
agglutinate.
• The same happens with anti-B and antigen B.
Rules for Donation
• You can give or receive from the same blood
group.
• The person receiving blood does not have any
antibodies against the donor’s antigens.
Blood Groups (Grade A)
AB
O
A, B, O
same
group
only
Blood Clotting
• Blood clots in order to seal wounds
• Vitamin K is important for this to happen
• Doctors use warfarin, heparin and aspirin to
prevent clotting
• Haemophilia is an inherited condition where
the blood does not clot
• It is a cascade process
Blood Clotting Cascade
cut
many factors, including
anti-haemophilia
vitamin K
Prothrombin
from the liver
calcium ions
Platelets exposed to
air at site of cut
thromboplastin
thrombin
Fibrinogen
in plasma
fibrin clot
Trachea
Alveoli (air sac)
Lung
Bronchiole
Intercostal
Muscles
Ribs
Bronchus
Pleural
membrane
Diaphragm
Respiration in Amoeba and Worms
Small, simple animals exchange gases like
oxygen through moist skin.
O2
O2
O2
O2
O2
O2
O2
Fish – Key Gas Exchange Facts
• Oxygen dissolved in water passes over fine gill
filaments
• Gill filaments have a large surface area
• They have a rich blood supply – they look red
• A bony gill bar supports the filaments
• Gill rakers sometimes stop particles of food
blocking the gills
Frogs
• Frogs snouts act as a pump.
• The frog takes in air, and the floor
of his mouth raises and lowers,
causing the pumping effect.
• Frogs also absorb some oxygen
through their skin.
• This means he doesn't have to
breathe quite as much as he
would if he didn't absorb through
his skin.
• Other amphibians have gills which
allows them to breathe in and out
of water
Human Ventilation
•
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Put the following in order
Intercostal muscles contract
Ribs move out and up
Diaphragm contracts and flattens out
Volume increases, pressure decreases
Air rushes in
Intercostal muscles relax
Ribs move down and in
Diaphragm relaxes and stretches
Volume decreases, pressure increases
Air rushes out
Efficient lungs
•
•
•
•
Large surface area of alveoli;
Moist surface;
Thin lining;
Good blood supply.
Terminology
• A spirometer is used to measure how much air is
breathed in and out
• When you are resting and breathing normally, you
are exchanging tidal air.
• Vital capacity - The amount of air that can be forced
out of the lungs
• Residual volume -The amount of air left in the lungs
after a maximal exhalation. The amount of air that is
always in the lungs and can never be expired
Larger volumes
Smaller volumes
males
females
taller people
shorter people
non-smokers
heavy smokers
professional athletes
non-athletes
people living at high
altitudes
people living at low
altitudes
Symptoms of Asthma (Grade C)
•
•
•
•
Shortness of breath
Wheezing
Coughing
Tightness in the chest
Treatment of Asthma (Grade C)
• Inhalers
– Preventer
– Reliever e.g. Ventolin (widens bronchioles)
• Primary care provided by doctors and nurses trained
in asthma management.
• Weight reduction advice for obese patients with
asthma to improve asthma control.
• Advice to smokers about the risks to themselves and
their children with asthma.
• Vaccinations to reduce respiratory infection, such as
flu.
Cause of Asthma (Grade A)
• Exact cause is not clear
• Combination of inherited, environmental,
infectious and chemical factors
Cause of Asthma (Grade A)
Sensitive airways
Trigger
Immune response
Airways constrict
More mucus produced
Body releases histamine
Airways inflamed
Less air available for gas
exchange in the lungs
Mucus plug
Starter - Waste Disposal
• Excretion – getting rid of waste
products made by the body.
– The lungs, liver, skin and kidneys all
excrete waste.
– The kidneys excrete water, salt and urea.
• Defecation – getting rid of solid waste
through the anus that cannot be
digested.
Function of the Kidney
• The kidneys filter the blood under high
pressure.
• They remove all waste products and any
excess water and salt ions.
• Any useful substances are returned
(reabsorbed) to the blood eg glucose,
some water, some salt.
• Urine is stored in the bladder.
Role of the Kidney - HIGHER
• The kidneys help to maintain the internal
environment by:
– First filtering the blood
– Reabsorbing all the sugar
– Reabsorbing the dissolved ions needed by the
body
– Reabsorbing as much water as the body needs
– Releasing urea, excess ions and excess water
as urine
Nephron Structure
Capsule
Glomerulus
Renal artery
Blood capillary
Sodium and
chloride ions
leave tubule
Renal vein
Glucose
reabsorbed
into blood
Collecting duct – waste to
ureter
Role of the Nephron (Grade A)
• A kidney contains about half a million
tubules that filter the blood
• They are U-shaped
• They contain a ‘filter unit’ – glomerulus
(collection of blood capillaries) surrounded
by a capsule
• The loop is where the blood selectively
reabsorbs useful substances such as
glucose and some water
• The tubule also regulates water and salt
levels
ADH – Anti Diuretic Hormone
• Urine concentration depends on how
much water is reabsorbed by the kidney
tubules
• This is controlled by ADH (made in the
pituitary gland)
• It is a negative feedback system
Menstruation
•
•
•
•
Day
Day
Day
Day
1-7: Menstruation/period
8-12: Uterus wall builds up
13-15: Ovulation, egg released from ovary
16-28: Uterus wall remains thick
Ovulation
Egg
Released
Thickness of uterus wall
Menstruation
Uterus lining
–uterus lining
starts to thicken
breaks down
up again
Uterus lining remains thick
waiting for a fertilised egg
Uterus lining
breaks down when
fertilised egg
doesn’t appear
Menstruation
• Hypothalamus in the brain triggers 2
hormones to be released from the
pituitary gland
– FSH (Follicle Stimulating Hormone) –
Stimulates a follicle in an ovary to start
developing
– LH (Luteinising Hormone) – controls the
release of an egg
Other Hormones
• As the follicle in the ovary develops it
releases oestrogen and progesterone.
• These control the growth of the uterus
cells and therefore the thickness of the
uterus lining.
If the egg is fertilised…
• The levels of progesterone remain high
• No more eggs develop or are released
• No FSH is produced
• The uterus lining does not break down
Reasons for Infertility
Not enough FSH produced
Inability to carry a foetus to term
Inability to fall pregnant naturally
Ovaries stop producing eggs at a young
age
• Blockage in the oviducts
• Partner with a low sperm count
•
•
•
•
Solutions for Infertility
• Not enough FSH produced – FSH injections
• Inability to carry a foetus to term – IVF and
surrogacy
• Inability to fall pregnant naturally - IVF
• Ovaries stop producing eggs at a young age –
egg donation
• Blockage in the oviducts – artificial
insemination
• Partners with a low sperm count – artificial
insemination
Mechanical Replacements
The lens in the
eye is replaced
with a plastic one
Hip joints can wear
out and are replaced
with a metal ball and
socket
The heart is
replaced with a
metal and plastic
pump
Knee joints can also wear
out and are replaced
with a metal hinge joint
Biological Replacements
The cornea of the
eye can be
transplanted
One kidney can be
transplanted
Bone marrow from inside
bones can be
transplanted
The whole heart
can be
transplanted
Both lungs, sometimes with
the heart, can be
transplanted
Blood is often transfused
during operations
Disadvantages of Mechanical Replacements
•
•
•
•
•
Size
Weight
Need a power supply
Materials must be inert, light and strong
Rejection must be controlled
Growth in Plants and Animals
• Animals normally only grow in the early stages
of their life
• Plants grow during all their life
• Animals grow all over their body
• Plants only grow from their meristems (tips of
roots and shoots)
• In animals or plants cells divide by mitosis to
make new cells to grow