Humans as Humans as OrganismsOrganisms

ContentsContents NutritionNutrition Digestive SystemDigestive System Circulatory SystemCirculatory System BreathingBreathing Respiratory SystemRespiratory System Aerobic RespirationAerobic Respiration Anaerobic RespirationAnaerobic Respiration Nervous SystemNervous System HormonesHormones HomeostasisHomeostasis DiseaseDisease DrugsDrugs

NutritionNutritionThe main food types are:

Carbohydrates (sometimes referred to as Starch) are required by our bodies as a source of energy. Example of food which carbohydrates can be found in are pasta, potatoes and rice.

Fats are needed to insulate our bodies and to make cell membranes. They also contain fat-soluble vitamins. Example of food which fats can be found in are cheese, butter, oils and margarine.

Protein are required for growth and repair. Examples of food which contain protein are meat, fish, eggs and cheese.

Fibre is important because it allows the muscles in our intestines to move the material along (called peristalsis). Fibre is not digested in our diet. Examples of food which contain fibre are wholemeal products e.g. bread, fruit and vegetables.

Digestive SystemDigestive SystemThe food we eat needs to be broken down into small pieces which we chew up into even smaller ones before swallowing them. Once the food gets to the stomach the food is broken down further by the stomach's muscular walls. This is known as physical digestion.

Substances which our body needs cannot be absorbed into our blood until they have been broken down further and converted into small soluble chemicals. Enzymes are responsible for this process. This process is called chemical digestion.

Peristalsis is the movement of food through the digestive system by the contractions of two sets of muscles in the walls of the gut. The two sets of muscles produce wave-like contractions enabling food to move down the gut.

Carbohydrate is turned into glucose, which our bodies need to make energy.Protein is turned into amino acids, required for cell growth and repair.Fats and oils are turned into fatty acids and glycerol, needed to insulate our bodies and make cell membranes.Vitamins and minerals do not have to be digested because they are already small enough to get into our blood.

Digestive SystemDigestive System

The Pancreas produces enzymes: carbohydrase, lipase, protease

The Stomach produces protease, HCl and pummels food with muscular walls

3. Large Intestine (Colon) is where indigestible food is passed to. Any excess water is absorbed before it is excreted from the anus.

2. The Small Intestine receives the food next and produces protease and lipase, food is absorbed into blood, large surface area by villi

The Gall Bladder stores bile after its been made by the liver

1. Chemical Digestion starts in the mouth through enzymes and saliva. The food is then moved to the stomach

VilliVilliVilli are small projections covering the inside walls of the small instestine. Food products pass into the blood stream through the villi.

Villi are located in the small intestine, and absorb very small molecules into the blood stream

All other molecules (indigestible) are passed into the large intestine

Circulatory SystemCirculatory System

1. Deoxygenated blood enters through the vena cava into the right atrium2. It’s then pumped through a valve into the right ventricle chamber3. And then up through the pulmonary valve into the pulmonary artery towards the lungs4. Oxygenated blood enters through the pulmonary veins into the left atrium5. It’s then pumped through a valve into the left ventricle6. And then through the aortic valve and out of the aorta to the rest of the body

The heart is a four-chambered muscular pump which pumps blood round the circulatory system. The right side of the heart pumps de-oxygenated blood to the lungs to pick up oxygen. The left side of the heart pumps the oxygenated blood from the lungs around the rest of the body.

How the Blood is TransportedHow the Blood is TransportedArteries (thick walled

muscular tubes) carry blood away from the heart at high

pressure in thick walled lumen

Veins (thin walled tubes) carry low pressure blood back to the heart. Veins have thinner

walls and valves to prevent backflow of blood

Capillaries (very narrow tubes) have thin walls to

allow glucose and oxygen to diffuse

through

BreathingBreathingWhen we breathe in and out we suck air into them then expel it again. Oxygen is absorbed from the lungs into the blood, and carbon dioxide is removed from the blood and breathed out from the lungs. This exchange is vital

AlveoliAlveoli AlveoliAlveoli are the final are the final

branchings of the branchings of the respiratory tree and act as respiratory tree and act as the primary gas exchange the primary gas exchange units of the lungunits of the lung

Used for exchanging gases:Used for exchanging gases: Deoxygenated enters lungs Deoxygenated enters lungs

from body, oxygenated from body, oxygenated enters capillaries from lungsenters capillaries from lungs

Advantages of alveoliAdvantages of alveoli:: MoistMoist Large surface areaLarge surface area Good blood supplyGood blood supply

Respiratory SystemRespiratory SystemRespiration is the release of energy from glucose or other organic substances. Energy is required for growth, repair, movement and other metabolic activities.

There are two main types of respiration, aerobic and anaerobic.

Aerobic RespirationAerobic RespirationAerobic respiration takes place in the presence of oxygen. Glucose molecules

react with oxygen molecules to form carbon dioxide and water molecules, with energy being released by the breaking of bonds in the glucose molecules.

Our bodies require energy for the seven life processesOur bodies require energy for the seven life processes

This energy is obtained from respirationThis energy is obtained from respiration

glucose + oxygen glucose + oxygen water + carbon dioxide + water + carbon dioxide + energyenergy

Glucose comes from our food, oxygen from breathingGlucose comes from our food, oxygen from breathing Water and carbon dioxide are exhaledWater and carbon dioxide are exhaled

Anaerobic RespirationAnaerobic Respiration Anaerobic respirationAnaerobic respiration occurs when oxygen is not occurs when oxygen is not

available. Glucose is only partially broken down, and lactic available. Glucose is only partially broken down, and lactic acid is produced - together with a much smaller amount of acid is produced - together with a much smaller amount of energy.energy.

Energy can still be produced without oxygenEnergy can still be produced without oxygen Only a little bit of energy is obtained from respirationOnly a little bit of energy is obtained from respiration

glucose glucose lactic acid + lactic acid + energyenergy

Anaerobic respiration occurs in humans when oxygen is not Anaerobic respiration occurs in humans when oxygen is not obtained quick enough (e.g. running fast)obtained quick enough (e.g. running fast)

Only 1/20Only 1/20thth energy amount is produced compared to aerobic energy amount is produced compared to aerobic Lactic acidLactic acid builds up, which causes muscle fatigue due to builds up, which causes muscle fatigue due to

oxygen debtoxygen debt This is overcome by deep breathing to oxidise the acidThis is overcome by deep breathing to oxidise the acid

Nervous SystemNervous System

e.g. you walk into a bright roome.g. you walk into a bright room Stimulus Stimulus receptor receptor CNS CNS effector effector response response

So…So…

Light intensity Light intensity eye eye brain brain eye muscles receive eye muscles receive information information eye muscles make pupil smaller eye muscles make pupil smaller

Electrical signals are carried around the body along Electrical signals are carried around the body along neuronesneurones

The nervous system is a means of gathering information about, and responding to, changes in the environment either inside or outside the body.

The nervous system is made up of receptors which respond to stimuli and pass on information about them. The central nervous system co-ordinates the information and responds by sending signals to the effectors, which bring about a response.

NeuronesNeurones There are 3 neurones:There are 3 neurones:

SensorySensory – carry signals from sense organs to brain – carry signals from sense organs to brain RelayRelay – carry messages from one part of CNS to – carry messages from one part of CNS to

anotheranother MotorMotor – carry signals from CNS to muscles – carry signals from CNS to muscles

Reflex ArcReflex Arc The subconscious movement from a stimulus that The subconscious movement from a stimulus that

can cause harm e.g. a bee stingcan cause harm e.g. a bee sting

The reflex arc does not require a conscious The reflex arc does not require a conscious action, which might be too slowaction, which might be too slow

So… the So… the brain is bypassedbrain is bypassed……

Stimulus Stimulus receptor receptor effector effector response response

HormonesHormones Hormones help to Hormones help to

regulate metabolic regulate metabolic processes in the bodyprocesses in the body

Hormones are Hormones are secreted into the secreted into the blood through blood through endocrine glandsendocrine glands

They travel in the They travel in the blood to organs where blood to organs where they take effectthey take effect

The endocrine system

Pituitary glandPituitary gland

TestesTestes

OvariesOvaries

OvariesOvaries

PancreasPancreas

PancreasPancreas

Adrenal glandAdrenal glandThyroid glandThyroid gland

Pituitary glandPituitary gland

Pituitary glandPituitary gland

GlandGland

TestosteroneTestosterone

ProgesteroneProgesterone

OestrogenOestrogen

GlucagonGlucagon

InsulinInsulin

AdrenalineAdrenalineThyroxineThyroxine

Luteinising hormone (LH)Luteinising hormone (LH)

Follicle stimulating Follicle stimulating hormone (FSH)hormone (FSH)

Anti-diuretic hormone Anti-diuretic hormone (ADH)(ADH)

HormoneHormone

Controls puberty in malesControls puberty in males

Maintains womb-lining; Maintains womb-lining; suppresses FSH production suppresses FSH production in pituitaryin pituitary

Controls puberty and the Controls puberty and the menstrual cycle in females; menstrual cycle in females; stimulates production of LH stimulates production of LH and suppresses production and suppresses production of FSH in pituitaryof FSH in pituitary

Controls blood sugar levels Controls blood sugar levels by decreasing uptake of by decreasing uptake of glucoseglucose

Controls blood sugar levels Controls blood sugar levels by increasing uptake of by increasing uptake of glucoseglucose

Prepares body for action Prepares body for action (fight or flight)(fight or flight)

Controls metabolic rateControls metabolic rate

Triggers egg release and Triggers egg release and progesterone production in progesterone production in ovariesovaries

Triggers egg ripening and Triggers egg ripening and oestrogen production in oestrogen production in ovariesovaries

Controls blood water level Controls blood water level by triggering uptake of by triggering uptake of water in kidneys water in kidneys

ActionAction

The Menstrual CycleThe Menstrual Cycle Four hormones are involved:Four hormones are involved: OestrogenOestrogen ProgesteroneProgesterone FSH (FSH (Follicle stimulating hormone )Follicle stimulating hormone ) LH (LH (Luteinising hormone )Luteinising hormone )

The Key stages areThe Key stages are1. The egg ripens in the ovaries - stimulated FSH 1. The egg ripens in the ovaries - stimulated FSH 2. Womb lining build-ups - stimulated by 2. Womb lining build-ups - stimulated by Oestrogen Oestrogen 3. Egg is releases - stimulated by the LH (about 3. Egg is releases - stimulated by the LH (about day 14) day 14) 4. Maintenance of uterus lining - stimulated by 4. Maintenance of uterus lining - stimulated by progesterone progesterone 5. Uterus lining breaks down - caused by low 5. Uterus lining breaks down - caused by low levels of oestrogen and progesteronelevels of oestrogen and progesterone6. Blood and tissue loss (menstruation) 6. Blood and tissue loss (menstruation)

HomeostasisHomeostasis Homeostasis is the body’s method of controlling Homeostasis is the body’s method of controlling

the internal conditionsthe internal conditions Controlling TemperatureControlling Temperature

– Too hot?Too hot? 1. Our hairs lie flat so we let more body heat out1. Our hairs lie flat so we let more body heat out 2. We sweat and the evaporation of this cools us down2. We sweat and the evaporation of this cools us down 3. Increased blood flow occurs through the skin to radiate 3. Increased blood flow occurs through the skin to radiate

out heatout heat– Too cold?Too cold?

1.Our hairs stand up trapping a layer of air which acts like 1.Our hairs stand up trapping a layer of air which acts like an insulatoran insulator

2. We stop sweating stopping the heat loss by evaporation2. We stop sweating stopping the heat loss by evaporation 3. Decreased blood flow occurs through the skin3. Decreased blood flow occurs through the skin

HomeostasisHomeostasis Controlling Blood Sugar LevelControlling Blood Sugar Level

– Blood Glucose level too high?Blood Glucose level too high? 1. Insulin injected by pancreas1. Insulin injected by pancreas 2. Glucose absorbed by tissues2. Glucose absorbed by tissues 3. Glucose absorbed by liver3. Glucose absorbed by liver 4. Blood glucose reduced4. Blood glucose reduced

– Blood Glucose level too low?Blood Glucose level too low? 1. Insulin not injected by pancreas1. Insulin not injected by pancreas 2. Less glucose absorbed by tissues2. Less glucose absorbed by tissues 3. Less glucose absorbed by liver3. Less glucose absorbed by liver 4. Blood glucose increased4. Blood glucose increased

Diabetes – This is a condition where people who suffer from Diabetes – This is a condition where people who suffer from this do not make insulin so it needs to be injectedthis do not make insulin so it needs to be injected

HomeostasisHomeostasis Controlling Body WaterControlling Body Water

– Too much water?Too much water? 1. Hypothalamus (part of brain) detects too much water in 1. Hypothalamus (part of brain) detects too much water in

bloodblood 2. Pituitary gland releases less ADH2. Pituitary gland releases less ADH 3. Kidneys absorb more water from blood3. Kidneys absorb more water from blood 4. More water reaches bladder and is lost through urine4. More water reaches bladder and is lost through urine 5. Blood water level returns to normal5. Blood water level returns to normal

– Too little water?Too little water? 1. Hypothalamus (part of brain) detects too little water in blood1. Hypothalamus (part of brain) detects too little water in blood 2. Pituitary gland releases more ADH2. Pituitary gland releases more ADH 3. Kidneys absorb less water from blood3. Kidneys absorb less water from blood 4. Less water reaches bladder and is lost through urine4. Less water reaches bladder and is lost through urine 5. Blood water level returns to normal5. Blood water level returns to normal

Fighting InfectionFighting Infection Microbes (an organism too small to be seen by the Microbes (an organism too small to be seen by the

naked eye) can enter the body through the mouth, naked eye) can enter the body through the mouth, nose and cuts or bites in the skinnose and cuts or bites in the skin

Microbes (bacteria and viruses) can Microbes (bacteria and viruses) can cause diseasescause diseases

Two typesTwo types of white blood cell: of white blood cell:– Lymphocytes – engulf pathogensLymphocytes – engulf pathogens– Phagocytes – contain antibodiesPhagocytes – contain antibodies

White blood cells White blood cells do 3 thingsdo 3 things::1)1) Engulf the microbeEngulf the microbe2)2) Produce antibodies to neutralise the microbeProduce antibodies to neutralise the microbe3)3) Produce antitoxins to neutralise the toxins released Produce antitoxins to neutralise the toxins released

by the microbeby the microbe

Tobacco & SmokingTobacco & Smoking Cigarettes are harmful in three ways:Cigarettes are harmful in three ways:

Nicotine – addictive drug that leads to heart disease. Nicotine – addictive drug that leads to heart disease. Nicotine raises blood pressure and narrows arteriesNicotine raises blood pressure and narrows arteries

Tar – coats the lining of the lungs Tar – coats the lining of the lungs less O less O22 is is absorbed. Tar contains carcinogens which cause absorbed. Tar contains carcinogens which cause cancerscancers

Carbon monoxide – poisonous gas which joins onto Carbon monoxide – poisonous gas which joins onto red blood cells making them incapable of red blood cells making them incapable of transporting oxygen around the bodytransporting oxygen around the body

DrugsDrugs

Distorted perception, Distorted perception, hallucinationshallucinations

Glue, paint, fuelGlue, paint, fuelSolventsSolvents

Lowers inhibitions, slowed Lowers inhibitions, slowed CNS and reaction timesCNS and reaction times

Alcoholic drinksAlcoholic drinksAlcoholAlcohol

Feeling of enormous energy, Feeling of enormous energy, hallucinationshallucinations

LSD, cannabisLSD, cannabisHallucinogensHallucinogens

Suppress pain receptors & Suppress pain receptors & neurones in CNSneurones in CNS

Aspirin, morphineAspirin, morphinePainkillersPainkillers

CNS slowedCNS slowedAlcohol, Alcohol, tranquiliserstranquilisers

SedativesSedatives

Increased alertnessIncreased alertnessCaffeine, nicotineCaffeine, nicotineStimulantsStimulants

EffectEffectExampleExampleDrug typeDrug type

SummarySummary Food is digested Food is digested v small molecules are absorbed into v small molecules are absorbed into

bloodblood The heart pumps oxygenated blood to the body, and The heart pumps oxygenated blood to the body, and

deoxygenated blood to the lungsdeoxygenated blood to the lungs Organisms inhale oxygen and exhale COOrganisms inhale oxygen and exhale CO22 Organisms respire to produce energy required to surviveOrganisms respire to produce energy required to survive

Glucose + oxygen Glucose + oxygen water + carbon dioxide + energy water + carbon dioxide + energy Anaerobic respiration produces energy Anaerobic respiration produces energy withoutwithout oxygen oxygen

Glucose Glucose lactic acid + small amounts of energy lactic acid + small amounts of energy Stimulus Stimulus receptor receptor CNS CNS effector effector response response Hormones help regulate the body’s metabolic rateHormones help regulate the body’s metabolic rate The body controls: water, temperature, glucose content by The body controls: water, temperature, glucose content by

homeostasishomeostasis The body’s white blood cells fight diseaseThe body’s white blood cells fight disease The body is affected in different ways by many types of drugThe body is affected in different ways by many types of drug