The Body Systems

Question 1

What are the body systems ?

Answer 1

-Cardiovascular
-Respiratory
-Gastintestinal
-Lymphatic
-Integumentary (bodie’s outer layer - skin, nails, hair, glands)
-Musculoskeletal
-Endocrine
-Urinary
-Nervous
-Reproductive

All working with each other and for each other

Question 2

What do all cells require ?

Answer 2

All cells require energy

Question 3

Why do all cells require energy ?

Answer 3

To carry out the common metabolic processes that keep them all alive
-e.g. maintenance of internal cell pH for cell enzyme function

To perform their specific functions
-e.g. cardiac muscle cell contraction to make the heart pump

Need energy to survive and carry out their specific function

Question 4

What is the cellular “currency” of energy and what is used to produce it ?

Answer 4

-The cellular “currency” of energy is ATP (adenosine triphosphate). Cells use ATP to be able to undertake their function
-Oxygen and nutrient molecules (e.g. glucose) which we obtain from food are used to produce this ATP
(See biochemistry lectures for more details)

Question 5

Explain the tissue hierarchy and the functions of each level

Answer 5

Cells (and associated extracellular matrix) form the 4 basic tissue types of the body:
-muscle, epithelia, nerves & connective tissue

The 4 basic tissue types form organs:
-An organ is a group of tissues acting together to perform a specific function(s)

Organs form systems:
-Collections of organs that have related functions and work together to carry out a common ‘goal’
-The goals are essential for survival

Cells work together to form tissues, tissues work together to form organs, organs have a main function and many mini functions to achieve this

Question 6

How do we get nutrients into our blood?

Answer 6

The Gastrointestinal (GI) system
-The GI tract runs from mouth to anus
-Large molecules are digested into smaller molecules which can then absorbed into the veins (and lymphatic vessels) of the small intestine
-The venous blood from the absorptive parts of the GI tract drains to the liver first
-The liver stores some nutrients, makes other products from them (can store some products), or returns them into the venous system. It can also metabolise/detoxify potentially harmful substances absorbed from the GI tract

Blue bits are veins, blood is nutrient rich

GI tract has many accessory organs which helps get nutrients into blood. Liver cleans blood and returns it into blood (heads to heart)

Question 7

How do we deliver nutrients to the cells?

Answer 7

The Cardiovascular (CV) system
-Consists of the heart and the blood vessels
-Veins are blood vessels that drain blood back towards the heart
-Absorbed nutrients FIRST pass in the veins of the GI tract to the liver
-Venous blood FROM the liver containing these nutrients then drains back to the heart
-The heart is the pump of the cardiovascular system
-Arteries carry blood away from the heart

Heart drives blood flow
Blood from liver pretty quickly will reach heart again, veinous blood from liver comes up into heart

Question 8

Describe the structure of the heart

Answer 8

2 sides, a right and a left - pump in synchrony with each other
The RIGHT side pumps VENOUS (deoxygenated) blood to the lungs
The LEFT side pumps ARTERIAL (oxygenated) blood to all the other tissues & organs

Question 9

Describe circulation

Answer 9

-The heart pumps oxygenated blood into arteries (aorta first)
-Arteries supply blood to arterioles (ateries get immer smaller, true arterioles are mini arteries)
-Arterioles supply blood to capillaries (capillaries are tiny and leaky tubes)
-Capillaries drain the blood into venules (venules are very small and narrow diameter veins)
-Venules drain the blood into veins
-Veins drain blood back towards the heart

Question 10

Where are capillary beds found and what is their function ?

Answer 10

Capillary beds found in organs and tissues
-This is where you get an exchange of nutrients from capillaries into surrounding cells and tissues
-Capillaries are leakly so nutrients can leak out and get into cells surrounding the bed

Question 11

How do we get oxygen into the blood ?

Answer 11

The Respiratory system
-Normal Air contains ~ 20% oxygen
-Air travels through the “respiratory tree” (pretty much tubes which get smaller and smaller as you go down and as the tubes pass down into lungs)
-Surface of the very thin walled alveoli is covered with many thin walled capillaries
-This allows oxygen to be transferred by diffusion into the blood
-This, now oxygenated blood, is returned to the heart to be pumped to all the other cells of the body

To make ATP we need oxygen, this is how we get it

Wall of alveoli is very very thin so things can pass through it and are surrounded by tiny tiny capilllaries (which are thin and leaky), at this interphase is where gas exchange occurs – oxygen in, C02 out (diffusion over two sides)

Question 12

How do we deliver oxygen to the cells?

Answer 12

The Haematological system (blood and bone marrow)
-Haemoglobin (Hb) within red blood cells (RBCs) reversibly binds oxygen in the lungs
-Carries it to all capillary beds where it is released to be delivered to the cells
-As well as the RBCs which transport oxygen, there are other cells within the blood: platelets and white blood cells

A low haemoglobin level in the blood is called anaemia. Anaemia can cause breathlessness as body tries to breath quicker to get more oxygen

Question 13

What systems are invovled in the delviery of oxygen to the cells ?

Answer 13

The cardiovascular and haematologial systems

Question 14

How else do we deliver oxygen to the cells ?

Answer 14

The Cardiovascular System
-At the capillary beds of all tissues and organs, oxygen and carbon dioxide diffuse between blood and cells down concentration gradients

Question 15

How do we produce lymph?

Answer 15

-Fluid “squeezed” out of capillaries to deliver nutrients by the blood pressure is mainly reabsorbed again before the blood reaches the venules
-Excess fluid left in the tissues, in the extracellular spaces, is called tissue fluid (If left to accumulate would cause swelling so is absorbed by lymphatic vessels)
-Once this fluid is taken up by lymphatic vessels it is called lymph
-Lymphnodes filtre and cleam lymph, traps germs, waste and unwanted substances. Lymphnodes are also part of immune system and can detect is there is anything dangerous which shouldn’t be there
-Thoracic duct: major lymphatic vessel in the body, returns lymph to large veins in the root of the neck (veinous angles of neck)

Only lymph thing you’ll see in dissection is thoracic duct because it is the biggest and everything else is really small

Question 16

How do we excrete waste products?

Answer 16

The Respiratory and Renal systems
-All cells produce waste products as a result of metabolic processes
-Carbon dioxide and water are produced as (waste) by-products of ATP formation; carbon dioxide and water can combine to form carbonic acid
-Lactic acid can be produced by muscles during heavy exercise
-The pH baance of the body is very fine and pH must remain within certain limits for e.g. enzyme function
-Our respiratory and renal systems are important in the removal of CO2 and (extra) acids from the body

Can’t let waste buid up, resp gets rid of C02 quite quickly, renal takes longer to remove waste

Question 17

What systems are involved in excreteing waste ?

Answer 17

-Respiratory
-Renal
-Gastrointestinal
Lymphatic

Question 18

How else do we excrete waste products ?

Answer 18

The Gastrointestinal, Renal and Lymphatic systems
-“Waste” can come in other forms, can’t let these build up so need to get rid
-“Cellular debris” dying cells shed from the internal lining of the GI tract and passed in faeces
-Indigestible foodstuffs pass out of the body via the gastrointestinal tract within faeces (such as fibre)
-GI tract bacteria, commensals and pathogens, pass via faeces (waste products from bacteria/viruses)
-Drugs deactivated by metabolism in liver and excreted in the faeces (or urine)
-Foreign bodies e.g. inhaled atmospheric carbon particles/microorganisms/cancer cells, can drain via lymphatics to lymph nodes (immune function)

These systems get rid of the other types of waste (types other than acid/water/C02)
Foreign bodies can be passed out by facaes, or absorption into lymph to be broken down by WBCs and debris can travel through blood and get peed out

Question 19

Which systems provide protection ?

Answer 19

-The Integumentary system
-The Lymphatic system
-The Nervous system

Question 19

How does the integumentary system provide protection ?

Answer 19

Our skin (integument) is the body’s first line of defence against the external environment

It provides our body with:
-A physical defence against trauma (external protection)
-A waterproof barrier (external protection)
-To a degree protects us against UV radiation (external protection)
-Helps to regulate body temperature (internal protection)

Skin is an organ

Question 19

What are the layers and structures of the skin ?

Answer 19

-Top later is epidermis
-Lower layer is dermins (skin follicles are here)
Arrector muscles which make hair stands on end by contracting and pulling hair up
-Blood vessels with nerves running up
-Lymphatic vessels
-Sweat glands (the pink thing)
-Superficial fascia – subcutaneous fat is found here which is where most of fat is – fascia is a connective tissue,
-Deep fasica
(Then you get down to muscles)

Question 19

How does the skin thermoregulate ?

Answer 19

-Arrector muscles cause hair to stand up straight - tries to form air barrier to keep in warm
-Fat to keep warm
-Sweat to keep cool
-Arterioles in skin constrict/dilate to help in temp management

Question 20

How does the lymphatic system provide internal protection ?

Answer 20

-A clinician needs to know the normal route that lymph takes when draining from a tissue or organ
-Normal lymph nodes cannot usually be palpated
-Lymph nodes fighting infection or being infiltrated by a spreading cancer usually enlarge and can then be palpated
-Also discrete areas of lymphatic tissue located in the body assist with the identification and destruction of invading pathogens

Lymph nodes filter lymph and check for and detect invaders, invaders passing through node can make them swell and become enlarged and palpable.
If you know where lymph nodes are you can check for swollen ones to check how far an infection has spread
Lymphnode biopsies in cancer to determine extent of cancer spead to nodes if has began to spread through system - can check the next nodes on

Question 21

How does the nervous system protect us ?

Answer 21

Provides internal and external protection
-Allows us to sense our environment and to effect an appropriate response
-Sensory part, motor part and central connections (in brain or spinal cord) between the two

Internal protection: Chemical levels on body can change: too much C02 is picked up by chemoreceptorsand sent to brain so we breathe faster to remove excess C02
External protection: Muscles cant move without nerve supply, sensation from eyes seeing scary, motor to muscles to run away

Protects us from internal and eternal environment and allows us to react to said environments

Question 22

What regulates the processes in our body ?

Answer 22

-The endocrine system consists mainly of a number of organs called endocrine glands found in various anatomical locations in the body -These glands all secrete hormones directly into their capillary blood -Hormones regulate many crucial physiological processes e.g. the release of insulin from the pancreas regulates the uptake of glucose into the cells Endocrine makes hormone which travel through blood to arrive at and regulate cells ## Footnote These systems work together to achieve regulation, endocrine makes hormone which travel through blood to arrive at and regulate cells.

Question 23

What protection does our musculoskeletal system provide ?

Answer 23

Internal and external protection -Closely linked to our nervous system -Skeletal muscle contraction moves the skeleton at joints to produce locomotion Our musculoskeletal system is both essential and protective: -It allows us to breathe (diaphragm needs to move) -Provides locomotion (to run from or fight scary things)

Question 24

Which system ensures survival of the species ?

Answer 24

The Reproductive system -Although the functioning of the reproductive system is not primarily aimed at the survival of the individual, it is necessary for survival of the species -Testis and ovaries are are the only primary reproductive organs, everything else is secondary/accessory ## Footnote Is different as all other systems work together to keep you alive, this one prioritises survival of species.