common requirements of living things - animals – chapter 5

Common Requirements of living things - ANIMALS – Chapter 5

Movement of substances into & out of unicellular organisms

Passive diffusion in and out

Cell Specialisation in Simple Multicellular Organisms

Sponge feeding

Cell Specialisation in Simple Multicellular Organisms

Cnidarians feeding

Cell Specialisation in Simple Multicellular Organisms

Cell Specialisation in Vertebrate Multicellular Organisms

Cell Specialisation in Vertebrate Multicellular Organisms

The different systems!Animal’s bodies are

composed of different systems, each system has

it’s own functions. All together these systems

work together to enable the animal to survive.

http://video.nationalgeographic.com/video/player/science/health-human-body-sci/human-body/human-body-sci.html

Obtaining nutrients and energy• Animals are heterotrophs must consume food in order to

obtain nutrients and energy.• Animals are adapted to obtain food in a variety of ways

python vs croc

Required Nutrients

• Carbohydrates - source of immediate energy for all living organisms. The monosaccharide glucose is broken down to make ATP in cellular respiration.

• Lipids- Fats and oils required for cell membranes, hormones and vitamins.• Amino Acids - The building blocks of proteins. The body can make some

amino acids but others it can’t make these are the 9 essential amino acids. Need to be regularly eaten.

• Vitamins - Organic compounds needed for cellular processes, e.g. making enzymes.

• Minerals - needed for structural components and for enzyme molecules.

Two Types of Digestion.Physical digestion.

– Food physically broken it down into smaller pieces in order to increase surface area and enable maximum efficiency of chemical digestion.

The Digestive System• Ingestion- intake of food into the body• Digestion- physical and chemical breaking down of food• Absorption- nutrient molecules move into the circulatory

system and ultimately into the cells.• Egestion/ Elimination- removal of waste from the body

Chemical DigestionBreakdown of macromolecules by enzymes- made in the gut, salivary glands and pancreas into molecules small enough to be absorbed through the alimentary lining.

Amylases- Break down carbs

Proteases- Break down protein

Lipases- Break down lipids

http://health.howstuffworks.com/human-body/systems/digestive/adam-200086.htm

Introduction to the Human Alimentary System animation

Digestion• Stomach - majority of digestion occurs

– Mechanical digestion occurs as the muscles crush and move the food.– Chemical digestion also occurs in the stomach, with the secretion of

gastric juices with have enzymes that break down the food.• Small intestine -further digestion occurs but only on proteins and

carbohydrates to break them down into their amino acid building blocks.

Digestion-video.htm

AbsorptionMost occurs in the small intestine. Food at it’s smallest is then absorbed by the cells of the intestine and passed along to the blood stream.

Task

• Draw a poster of the human digestive system, using the image on page 110.

• Label the drawing and explain the role of each word.

• Colour in the parts of the digestive system that are involved in ingestion, digestion, absorption and egestion.

Other mammals• Different diets require different digestive systems. • Breaking down cellulose requires the enzyme cellulase. • Mammals can’t make this enzyme.• Cows have a 4 chambered stomach. • They chew and then regurgitate their food and chew it again before sending it

to the rumen where heaps of cellulose digesting bacteria live and allow the breakdown of the cellulose to occurs.

Carnivore v Herbivore

Caecum: a pouch extension at the junction of the small & large colon which in herbivores contains cellulose digesting bacteria.

Herbivorus mammals with higher fibre diets may have larger caecums to maximise the opportunity for cellulose digestion by bacteria.

Digestion in birdsMost (not all) birds have :• a crop for temporary storage • a glandular part the proventriculus which

secretes mucus , HCl & enzymes• a muscular gizzard which may contain grit or

small stones which grinds and mixes the food and enzymes etc.

The Circulatory System

Internal transport systems

• distribute nutrients, gases and collect and remove wastes.

• transport hormones and blood.• Blood is also vital in defence,

immunity, blood clotting and transfer heat around the body of mammals and birds.

Open Circulatory SystemNo specialised transporting fluid.Instead interstitial fluid is moves freely around the body before eventually returning to the heart.Very low blood pressure and long circuit times.

Closed circulatory systems• Blood is enclosed in a system of vessels

surrounding a muscular heart.• Blood is returned very rapidly to the heart

and there is a higher blood pressure.• Blood is also separated from the interstitial

fluid vessel walls allowing the blood to be used for transport and defence.

• Small molecules like nutrients, gases, water and waste are freely exchanged by diffusion across capillaries.

• Because larger molecules(blood proteins) can’t diffuse out of the blood, this exerts osmotic effect drawing water back into the blood.

Closed Circulatory System

Closed System 2 Chambered Heart

Closed System 3 Chambered Heart

Closed System 4 Chambered Heart

Mammalian Transport Systems• There are 2 transport systems in

mammals:– The blood circulatory system-

majority of the animal’s transport needs.

– The lymphatic drainage system-open system that maintains osmotic and fluid balance in tissues and in immune defence.

Internal transport systems

Features of effective transport systems• Large surface area for exchange

both with the environment and internally.

• A reliable and responsive way of moving fluid(blood) around the body.

• A fluid that can carry the maximum amount of material.

• A way to regulate transport according to the needs of the body.

The human circulatory system

– A fluid material in which substances are transported; blood

– A system of blood vessels or spaces throughout the body in which fluid moves

– A pump such as the heart that pushes through the blood vessels and spaces.

THE CARDIOVASCULAR SYSTEM = heart and blood vessels

Blood

Red blood cells

• Biconcave • Very flexible• No nucleus • Packed with haemoglobin• Main function is

transporting gases

White blood cells

• Larger than red blood cells• About 1WBC to every 700

RBC• Several types but all

involved in defence.– Phagocytes: remove debris

and fight infection– Lymphocytes: produce

antibodies.

PlateletsFragments of cells, important in preventing blood loss and promoting blood clotting.

Arteries and Veins• Arteries carry blood away from the heart.• Veins carry blood towards the heart.• Arteries and veins have the same number of walls but arteries

have more muscular walls and veins more elastic walls.

Blood Movement in the Veins

Arteries• Because of their thicker

walls they can withstand greater pressure.

• Arteries flow into arterioles that then flow into capillaries.

• Blood pressure decreases as blood flows further along.

• Pressure in veins is much lower than in arteries.

• Blood moves along due muscles compressing the veins.

• Veins have lots of one way valves, that push the blood towards the heart.

• In the legs the blood has to be returned against gravitational pressure.

• The negative pressure in the lungs assists in drawing the blood up from the legs.

Veins

Capillaries• Tiny, many branched blood

capillaries provide a vast surface for exchanging blood.

• Most cells are no more than 1mm from the nearest capillary.

• Same diameter as a red blood cell, so they fit in one by one.

• When the wall of a red blood cell presses on the capillary wall there is an exchange of oxygen and carbon dioxide.

http://www.youtube.com/watch?v=CjNKbL_-cwA

Mammalian HeartFour chambers:The Atria (singular: atrium):

– Two top chambers, thinner walls.The Ventricles:– Two bottom chambers, thicker

walls.

One way valves ensure blood flows in one direction.

The heart is very coordinated first the atria contract forcing the blood into the ventricles then the ventricles contract.

Blood Circulation2 pathways-– To and from the lungs. The

pulmonary pathway.– To and from the rest of the body.

The systemic pathway.

The heartVeins and arteriesPulmonary vesselsSystemic vesselsCapillariesBlood

Blood pressure

• Caused by the contraction of the ventricles.

• The right ventricle is much thinner than the left so the pressure caused by the left ventricle is greater than the right.

• In the arteries blood pressure changes with every heart beat, this is the pulse you hear on your wrist.

• The higher systolic pressure occurs when the ventricles contract.

• The lower diastolic pressure occurs when the ventricles relax.

BLOOD PRESSURE• Blood pressure is described by these two limits. • Normally this is 120/80mmHg, so that is the systolic pressure/diastolic

pressure.

Right Atria receives

deoxygenated blood from body

Right Ventricle pumps

deoxygenated blood to lungs

Left Atria receives oxygenated blood

from lungs

Left Ventricle pumps out aorta

to the body

Vena cavae Aorta

Exchanging Gases

Exchanging gases with the environment

• All organisms must exchange gases with their environment, usually oxygen and /or carbon dioxide.

• Some unicellular and small multicellular organisms and plants can directly exchange gases with their environment.

• Larger animals have a higher metabolic rate and require highly developed gas exchange systems.

Respiratory Surfaces

Characteristics of Respiratory Surfaces• Diffusion of gases from high concentration to low concentration• Large surface area, • Thin • Moist• Vascularised

Respiratory Surfaces for Gaseous exchange

• Water ventilation- Gills– Supported by water and skeletal

rod.– In axolotles water passes over the

external gill surface– In fish water flows through the

mouth of the fish and then is pushed over the Internal gills when the mouth is closed.

– Fish gills have counter current flow. Water goes one way and the blood the other way.

– Fish extract 80-90% of oxygen from water, mammals only extract 25% from air, (however air has a lot more oxygen than water).

• Breathing air requires less energy than breathing water.

• There is much more oxygen in air than in water. (21% )

• Disadvantages of breathing air are water loss, because water evaporates continuously.

• Enclosing the lungs in the body protects

• them from physical damage and reduces water loss.

Terrestrial Air Breathers

Gas Exchange in Mammals

Gas exchange in mammals• First air is drawn in through the

pharynx (back of the throat.• From there air passes into the

airways- the trachea, paired bronchi and branching bronchioles.

• Both the trachea and the bronchi have ciliated cells on their surface and they secrete mucus, which protects the lungs against dust and bacteria.

• Finally air enters the air sacs called alveoli, it is here that gas is exchanged into the blood stream.

• The alveoli is made up of only 1 layer of cells which is covered in blood capillaries.

http://bcs.whfreeman.com/thelifewire/content/chp48/4802002.htmlhttp://www.youtube.com/watch?v=HiT621PrrO0

http://www.youtube.com/watch?v=mmpzIG9afJA&feature=related

Tidal Volume:• The volume of air moved in and out of your lungs in each breath.• When we breath in and out we never fully empty our lungs there is always

some stale air left over in the lungs, in our next breath we take this stale air back in.

• This stale air and a fluid called surfactant which covers the alveolar surface, protect the alveoli from collapsing in on themselves.

Transporting Gases• When breathing we supply air to the lungs

oxygen diffuses into the capillaries surrounding the alveoli.

• The blood carries the oxygen around the body.• So in many animals there are molecules that

increase the oxygen carrying capacity.• In humans this oxygen carrying molecule is

found in red blood cells and is called haemoglobin.

• Each haemoglobin molecule can attach to 4 oxygen molecules.

• It contains iron which assists in combining with the oxygen molecules.

Carbon Dioxide out• When cellular respiration

occurs, carbon dioxide is produced as a waste product this must be released if not to cause changes in pH.

• Carbon dioxide carried – dissolved in the plasma– by haemoglobin in the

red blood cells.

http://www.youtube.com/watch?v=5LjLFrmKTSA&feature=related

Excretion

Waste Removal and Water balance

• The human body and in fact all organisms are not 100% efficient at converting all the raw materials ingested into useful substances.

• Which means we have waste products.– CO2 is a waste product of cellular respiration– Protein breakdown results in nitrogen waste

• This then is excreted as either ammonia, urea or uric acid

What organs gets rid of the above 2 waste products?

The Urinary SystemKidneys

The kidneys are the organs that removes nitrogenous waste from the body.

The nephron structure and function

Kidney flowchart of events

Glomerulus Bowman’s capsule

Proximal tubule

Loop of henle

(descending)

Loop of henle

(ascending)Distal tubule

Collecting ducts Bladder Excreted

Perspiration and water balance• Sweat or perspiration is another way to get rid

of nitrogenous wastes. It’s composition is similar to that of plasma but without proteins.

• The amount of water taken into the body must equal the amount of water lost. The amount of water kept by the body is determined by a hormone called the Antidiuretic hormone.

http://mycozynook.com/102RGCh23OH.htm

http://people.eku.edu/ritchisong/birddigestion.html