Healthy Body Systems

Hypothalamus is the part of the brain and endocrine
system that is responsible for thermoregulation.
--> sends chemical signals to muscles, glands, organs
and nervous system.

Our blood vessels constrict when our bodies are too
hot, and expand when our bodies are too cold

37 degrees is the optimal temperature at which
our bodies function normally.
--> cells don't function properly when our core
temperature is changed too drastically.

The dermis layer of the skin is where our body's water
is stored
--> this water, plus salt, are brought to the surface of
the skin when we are hot to form sweat. It's purpose is
to cool on top of the skin due to evaporation to reduce
the body's temperature.

Our body's will slowly stop sending chemical signals
to parts of the body as the set point is reached again.

The nervous system and the endocrine system work
together to maintain maturation and homeostasis.

STIMULUS-> RECEPTOR-> CONTROL CENTRE->
RESPONSE
e.g. when our hand touches a hot stove, receptor
cells in our fingers recognise that it is hot and a
message is sent to the control centre, or brain, saying
that we have touched a hot surface. a reflex response
is carried out to remove our hand from the hot surface
--> reflex responses are vital to ensuring we don't cause
serious injury to ourselves.

When we are cold, our muscle contractions are reduced by
carbohydrates being relocated and our muscles produce lactic
acid. Our nervous system also slows down when we're cold to conserve energy.
--> NS slowing down and the production of lactic acid acts like a chemical signal telling our bodies to slow down to retain heat.

Our excretory systems prevent salt and urea from
building up in our bodies.

Kidney's remove toxins from the blood, which then travels
down the uterers as the form of urine and stored in our
bladder's until we go to the bathroom.

We also excrete waste through faeces.
--> the food we eat is broken down by digestive
enzymes in both our saliva and in our gut. Once
this food has been broken down into a liquid, it
travels into the small intestine where nutrients is
absorbs by villi that lines the wall of the intestine.
The nutrients we need is absorbed into the blood,
and any left over material passes through into the
large intestine and bowel where it is kept until we
go to the bathroom.

The respiratory system is also responsible for eliminating
waste.
--> our lungs breathe in air filled with a combination of
oxygen, CO2 and nitrogen. We only have need to keep the
oxygen in our bodies, which is passed into the blood in the
lungs via small sacks called arioli. CO2 from the air and from
within our bodies (produced by cells as a waste product of
converting food to energy) is exhaled back into the air as it
causes our bodies to become too acidic and our cells would
die.

Earwax is another way we eliminate waste.
--> sticky substance called cerumen is made up of
germs and dirt, but also protects our ears by keeping
them moist and prevents infection. The dirt and germs
that get stuck in the cerumen forms the earwax and
leaves the body when the earwax falls out.

Our noses and ears have small hairs that help prevent
dirt and germs from building up in our mucous
membranes.

Sweat is not only produced to cool us down, but
it eliminates waste as well.
--> waste products like extra salt and sugars, urea and ammonia are excreted when we sweat.

Immune system and blood cells

The skin and mucous membranes are the body's
first line of defence
--> main role is to protect the bodies internal tissues
and organs from infection

When germs do get into the body, the immune
system then takes over to destroy them

Leukocytes (white blood cells) both B and T are the main
cells that are make up the immune system
--> travel through the body looking for any disease-
causing germs and destroy them

Lymph nodes are an essential part of the immune system
-->filter foreign particles and cancer cells from the body.
Located in the neck, armpits, groin and behind the knees.

Lymphatic system transports B and T leukocytes into
the bones where blood cells are made
--> bone marrow is where the formation of red and white
bloods cells and platelets takes place

Having healthy bone marrow cells is essential because
our blood cells don't live for long in our body and have
to constantly be re-produced
--> without red blood cells, we couldn't transport oxygen
around the body. Without white blood cells we couldn't
fights infection and without platelets we'd all be
haemophiliacs.

Antibodies are essential proteins that are formed when
new germs enter the body
--> they're produced by B-leukocytes and attach onto
antigens that cause diseases, whilst other cells work
to destroy the cells, so it then remembers that germ. Once the antibody has been produced it then remains in the body to protect us from that infection if it returns in the future. We may still show symptoms, but our bodies will be able to fight the infection quicker. Different antibodies fight different
infections.

We develop our immunity naturally, from vaccinations
and from our mothers.
--> naturally being being exposed means we get sick
and develop our antibodies that way. Vaccinations
help to develop antibodies before we get sick (usually
with more serious illnesses). After birth, we get some
of our immunity from our mum if she has been
vaccinated during birth, during the first 6 months.

Role of the urinary and respiratory systems.

Blood electrolytes include potassium, chloride
sodium and bicarbonate.
--> they help to regulate nerve and muscle function,
maintain pH levels and water levels.

Kidney's maintain electrolyte levels by filtering waste products
out of the blood and converting it to urine.
--> the kidney's main role is to monitor the bodies consumption and excretion of water and electrolytes.

Water intake is balanced by water loss. This means,
when the body is losing water, the kidney's will produce
small amounts of concentrated urine to conserve water.
Kidney's will produce larger amounts of urine when there
is too much water as well. Everything is balanced.

Water is mostly lost through urine, but also through
faeces and the respiratory tract.

When the body is dehydrated, we draw water from
the blood, to maintain both blood concentration and
water levels.

We lose water through breathing in the form of water
vapour. How much water is lost through breathing is
dependent on how humid the air is. It's estimated we lose
~400mL of water per day by breathing.

Carbonic acid and bicarbonate are the two pH stabilising
chemicals is the body.
--> carbonic acid neutralises excess bases and bicarbonate
neutralises excess acids.

Exhaling CO2 rids the body of some acids
--> breathing too fast (hyperventilating) causes
too much acid to be release, creating an alkaline
environment which isn't compatible with
consciousness, causing us to faint. The same happens
when we hold our breathe for too long as our bodies
become too acidic.

Cardiovascular centre, located in the brain stem, detects changes in pH and blood pressure. Affects these changes by
sending nerve impulses to the heart, and regulates stroke rate
(amount of blood pumped).
--> both of these changes maintain the heart's cardiac output.
BPM x stroke volume = cardiac output

Our bodies adjust quickly to changes in physical activity
--> pressure senses in blood vessels detect an increase in blood pressure e.g. when we start exercising sends a message to the brain via the nervous system telling the heart to decrease the number of contractions and relax blood vessels
(vasodilation) to decrease blood pressure.

If our bodies suddenly lose a lot of blood, the sudden drop in
blood pressure will signal hormones (renin) to be released which tell the kidney's to retain salt and fluids to maintain blood density.

Kidney's are the primary organ responsible for maintaining healthy blood pressure.
--> chemical signals trigger the kidneys to increase urine productions when blood pressure is too high, and decrease urine production when blood pressure is too low. The ratio of blood to fluids to water is controlled in the kidney's.

When our bodies have higher blood flow in one area of the body, blood vessels will widen in another area to balance flow and blood pressure.

Renin is produced in the kidney's that causes vasoconstriction

Neurotransmitter called catecholamine activates the fight-or-flght response and responds when blood pressure falls.

Active range of motion refers to someone physically
moving the joint and subsequent parts of the body
on their own.

Passive range of motion means someone is moving
the joint for them.

Range of motion (ROM) is how far a joint moves
during physical activity.

Without ROM exercises, our joints and muscles would
lock and lose their ability to functions and move
properly
--> patients who are bed-ridden face the risk of developing
muscle atrophy if they don't do passive physical activity.

It is much easier for patients who can move independently to gain their full ROM.

Passive movement is sometimes also used by doctors
to test hoe far a. joint can move before deciding whether
they require passive or active treatment.

When muscles aren't being used frequently, they become
weak or stiff and unable to support the joint.
--> using resistance bands is the best way to start muscle
movement again after a period of being stationary e.g. after
having a knee replacement.

People who have a limited ROM can also have poor
circulation as they are unable to move and circulate
the blood around the body.
--> exercise is a good way to prevent pools of blood
forming in the lower portion of the body, as well as
improving heart health by helping it pump blood
around the body through movement.

Limbs can start to curl inward towards the body in severe
cases when a patient is paralysed, for example.
--> muscle tissue starts to decay and joints stiffen. Movement
prevents this from happening by lubricating the joints. In
these situations, it's likely passive ROM is required.

Exercise is a good way to reduce pain as well
-->whilst it will be painful in the beginning, it reduces
pain in the big picture by reducing the risk of getting
diseases like muscle atrophy which causes bad deformities.

We use more energy during active activity than passive
because we and exerting ourselves, rather than having
someone move our bodies for us.
--> we need physical activity to keep ourselves healthy and well to have improved circulation and muscle ROM.