Topic 2a Tissues, Organs And Organ Systems

Question 1

What are Tissues

Answer 1

Tissues are a group of similar cells that work together to perform a particular function

Question 2

What are organs

Answer 2

An organ is a group of different tissues that work together to perform a specific function

Question 3

What is an organ system

Answer 3

An organ system is a group of organs working together to perform a specific function

Question 4

What is the function of muscular tissue and give an example

Answer 4

Muscular tissue contacts to move whatever it is attached to.

Example - muscular tissue contracting to move the wall of the stomach in order to churn food.

Question 5

What is glandular tissue and give an example

Answer 5

Glandular tissue makes and secretes enzymes for digestion as well as hormones for chemical messages

Question 6

What is epithelial tissue

Answer 6

Epithelial tissue covers some parts of the body for instance the small intestine and contains cells used for absorbtion

Question 7

List all the main organs contained within the digestive system starting from top of diagram to the bottom and give a brief description of each organs role

Answer 7

Mouth/teeth - entrance to where food goes in and is broken down by chewing
Tounge - move food around to aid chewing
Salivary glands - produce digestive juices (Amalayse enzymes for digestion in the mouth)
Oesaphagus - leads down into the stomach (peristatas is the muscle contracting in a wave like motion to move food down)
Liver - Produces Bile which emulsifies fats and neutralises stomach acid
Gall Bladder - stores bile
Stomach - where food is digested and produces protease, HCl and pummels food with muscular walls
Small intestine - produces protease and lipase, food is absorbed into blood glucose, ions. It large surface area given by villi
Food traces along the apendix to the Large Intestine
Large Intestine - Re absorbtion takes place and indigestible food is passed to. Any excess water is absorbed before it is excreted from the anus

Question 8

Explain the purpose of the lungs

Answer 8

The purpose of the lungs is to perform gas exchange. Oxygen from the air is needed for respiration. Carbon dioxide also needs to be remevod from the blood.

Question 9

What is the thorax and the main structures of it

Answer 9

The thorax is the the top part of your body and is separated from the lower half by the diaphragm.
The lungs are protected by the rib cage and surrounded by the pleural membrane.
Air is breathed in and travels down the trachea (windpipe) to two tubes called bronchi.
The bronchi then separate into smaller tubes called bronchioles which end at small bags called alveoli where gas exchange takes place.

Question 10

why are the alveoli surrounded by lots of capillaries

Answer 10

Because this is where gas exchange takes place. Oxygen from the alveoli diffuses out into the blood cells in the capillaries and carbon dioxide in the blood cells diffuses into the alveoli

Question 11

What is the function of the circularity system

Answer 11

To carry food and oxygen to every cell in the body

To carry waste products like carbon dioxide and urea to where they can be removed from the body.

Question 12

What makes up the circulatory system

Answer 12

Heart, Blood and Blood vessels

Question 13

The circulatory system is made of two separate circuits joined together, explain the function of each circuit

Answer 13

The right ventricle pumps deoxygenated blood from the heart to the lungs and then oxygenated blood from the lungs to the heart

The left ventricle pumps oxygenated blood from the heart to the rest of the body and pumps deoxygenated blood from the rest of the body back to the heart

Question 14

Describe the structure and function of the heart

Answer 14

The function of the heart is to keep blood flowing around the body.
The heart consists of four chambers The Right Aitrium, Right Ventricle, Left Atrium Left Ventricle

Question 15

What are the main blood vessels leading in and out of the heart chambers

Answer 15

Vena Cava - where blood enters the heart
Pulmonary Artery
Aorta
Pulmonary Vein

Question 16

Describe the path of deoxygenated blood in the heart (Right Ventricle)

Answer 16

Deoxeygenated Blood from the body enters the heart in the Vena Cava
Moves down into the Right Atrium
Passes through a valve
Into the Right Ventricle
The ventricle contracts forcing blood into the pulmonary artery where deoxygenated blood is carried to the lungs for gas exchange

Question 17

Describe the path of oxygenated bloodflow in the heart (Left Ventricle)

Answer 17

Oxeygenated Blood Enters the heart via the Pulmonary vein
Moves down into the Left Atrium
passes through a valve
Into the Left ventricle
The ventricle contracts forcing Oxygenated blood into the Aorta out of the heart to the organs through arteries and veins

Question 18

Why is the muscle thicker around the Left Ventricle than the Right Ventricle

Answer 18

The Right Ventricle only has to pump deoxygenated blood back to the lungs where as the right ventricle has to pump oxygenated blood around the whole of the body hence the need for more muscle to perform this function as blood is flowing at a higher pressure

Question 19

What is the trick for remembering the path of blood in the heart

Answer 19

VAVAVAVA
Vena cava - right Atrium - right Ventricle - pulmonary Artery
pulmonary Vein - left Atrium - left Ventricle - Aorta

Question 20

Describe how the resting heart rate is controlled in a healthy heart

Answer 20

Controlled by a group of cells in the right atrium wall that act as a pacemaker producing electronic impulses which cause muscle cells to contract

Question 21

Describe what a pacemaker is and how it works

Answer 21

A Pacemaker is used to control the heartbeat of a heart if the natural cells don’t work causing the patient to have an irregular heartbeat. The device is placed under the skin and has a wire going to the heart. It sends electronic impulses to the heart causing the heart to beat in a regular manner.

Question 22

Describe the structure and role of an Artery

Answer 22

Blood vessels which carry blood away from the heart toward the organs.
They branch into capillaries.
Artery walls contain thick layers of muscle and elastic fibres to allow them to withstand the high pressures at which blood is pumped from the heart, stretch and spring back to shape.
The walls are thick compared to the Lumen (centre hole of the artery)

Question 23

Describe the structure and role of Veins

Answer 23

Veins carry blood toward the heart
Have a larger lumen than arteries to help with blood flow despite the lower pressure
Contain valves to keep blood flowing in the right direction and prevent the back flow of blood

Question 24

Describe the structure and role of Capillaries

Answer 24

Capillaries have very thin walls to allow for the exchange of substances carrying food oxygen to cells and taking away waste materials like carbon dioxide. They are Usually only One Cell thick (Short diffusion pathway)
They are very close to every cell
Have a large surface area compared to volume.
Very Small Lumen.
Capillaries join up to form veins.

Question 25

What is Blood

Answer 25

Blood is a tissue - its a group of cells that work together to perform a function

Question 26

Describe the formation of Oxyhaemoglobin in the lungs

Answer 26

In the lungs oxygen diffuses into blood - the oxygen combines with haemoglobin in red blood cells to become oxyhaemoglobin

Question 27

Describe the break down of Oxyheamoglobin in body tissues

Answer 27

Oxyhaemoglobin splits into Haemoglobin and oxygen to release oxygen to the cells

Question 28

Describe the function of White Blood cells

Answer 28

They defend against microorganisms that cause disease
They engulf unwelcome microorganisms and digest them (A process called Phagocytosis)
Produce antibodies
Produce antitoxins to neutralise toxins
They do have a nucleus

Question 29

What are Platelets

Answer 29

Platelets are small fragments of cells that help blood to clot
They have no nucleus
They stop microorganisms form getting in at a wound.
A lack of platelets can cause excessive bleeding and bruising

Question 30

Describe what Plasma is and the role in plays within the body

Answer 30

Plasma is a liquid substance which carries virtually everything in blood. It carries
Red and White blood cells and platelets
Soluble products of digestion absorbed from the small intestine i.e Glucose amino acids
Carbon dioxide from organs to the lungs
Urea from the liver to the kidneys
Hormones
Proteins
Antibodies/antitoxins produced by white blood cells

Question 31

What tissue covers the whole of a plant

Answer 31

Epidermal tissue

Question 32

Name all the tissues that together form organs in a plant

Answer 32

Epidermal tissue - Covers the whole of the plant helps reduce water loss by evaporation (waxy cuticle)

Palisade Mesophyll tissue - this is part of the leaf where photosynthesis happens located near the top of the leaf where the can get the most sunlight (contain chloroplasts)

Spongy Mesophyll tissue - this is found in the leaf and contains big air spaces to allow gases to diffuse in and out of cells

Xylem and Phloem - They transport water mineral ions and food around the plant

Meristem tissue - this is found at the growing tips of shoots and roots and is able to differentiate into lots of different types of plant cells allowing the plant to grow

Question 33

Why is the upper epidermis of a leaf transparent?

Answer 33

The upper epidermis of a leaf is transparent so that light can pass through it to the palisade layers

Question 34

How are the tissues of leaves adapted for efficient gas exchange?

Answer 34

The lower epidermis is full of tiny holes called stomata which allow Carbon dioxide to diffuse directley into the leaf. The air spaces in the spongey mesophyl tissue increase the rate of diffusion as they allow more gasses to diffuse in and out at one time.

Question 35

What are pholem tubes

Answer 35

Pholem tubes transport food made in the leaves to the rest of the plant for immediate use (in the growing regions or for storage) sucrouse amino acids

Question 36

What is translocation

Answer 36

Translocation is the name given to the process of the movement of food in the phloem tubes. Transport of food (usually dissolved sugars Cell sap for energy or storage) from the leaves to the rest of the plant and from the roots up to the leaves in both directions.
TRANSLOCATION = PHLOEM TUBES

Question 37

What are Pholem tubes made up of

Answer 37

elongated columns of cells with pores in the ends walls to allow cell sap to pass through.
PHOLEM = TRANSLOCATION

Question 38

What are xylem tubes made up of

Answer 38

Dead cells joined end to end to form a hollow tube strengthened by lignin

Question 39

What is the function of the xylem tubes

Answer 39

To carry up water and ions up from the roots to the stem and the leaves XYLEM = TRANSPIRATION

Question 40

What is transpiration

Answer 40

Transpiration is the process by which water evaporates from the surface of the leaves.
Transport water and minerals up from roots up the stem to the leaves
Dead Xylem cells end to end
Long hollow tube strengthened with lignin
Chain of water molecules evaporating from the plant through the stomata out of the leaves = Transpiration stream

Question 41

Describe the transpiration process using the transpiration stream

Answer 41

• Water from inside the leaves evaporates and diffuses out of the leaf, through the stomata
• This creates a slight shortage in water in the leaf and so more water is drawn up through the xylem from the rest of the plant
• This in turn means more water is drawn up from the roots and so there is a constant transpiration stream of water through the plant

Question 42

What factors affect the transpiration rate

Answer 42

• Light Intensity = Brighter the light the greater the transpiration rate. This is because the Stomata is the main way in which water diffuses out of the leaves of a plant. Stomata begin to close as it gets darker. Photosynthesis cant happen in the dark so the stomata don’t need to be open to allow carbon dioxide to diffuse into the plant. Therefore very little water can escape as the stomata are closed
• Temprature = The warmer it is the more energy the water particles are given to evaporate and diffuse out of the leaves
• Air Flow =The stronger the wind the greater the rate of transpiration. This is because if there is a lack of air flow, the water evaporated during transpiration process just surrounds the leaf and does not move away. This in turn affects the concentration gradient of water between the inside and the outside of the leaf maintaining both a high concentration of water inside and outside the leaf. Lack of air flow means the water remains, therefore the rate of diffusion doesn’t happen as quickly (Air flow means the water is swept away so there is a lower concentration of water outside than inside the leaf.
• Humidity = Similar to air flow if there is greater humidity in the air there is more water in the air so there isn’t much difference between the water on the inside of the leaf and the water outside the leaf. Diffusion rate increase when the concentration gradient has a larger visible difference.

Question 43

What is a potometer

Answer 43

A Potometer is a piece of apparatus used to measure the uptake of water by a plant

Question 44

What are guard cells explain there function

Answer 44

Guard cells are cells which surround either side of the stomata and control the opening and closing of the stomata. When the plant has lots of water the guard cells fill up opening the stomata ready for gas exchange needed for photosynthesis. When the plant is short of water the guard cells lose water becoming flaccid making the stomata close. This in turn helps stop the loss of water (water vapour escaping).

Question 45

Throughout the day the rate at which carbon dioxide diffuses into the leaf changes. explain how change in c02 concentration in the air spaces outside the cells could slow the rate of diffusion.

Answer 45

Diffusion is the movement of particles through a partially permeable membrane from a high concentration to a low concentration. If the c02 concentration outside the leaf is lowered then the rate of diffusion will decrease as there will be less of a visible difference in the concentration gradient

Question 46

Desert plants are adapted to survive in hot dry conditions. explain how the following adaptations help the plant to survive in the desert.

1. stomato remain closed during the day, when its hat and dry. only openeing when its cool at night.
2. stomata are located in sunken pits. this helps them to trap water vapour close to the surface of the plant.

Answer 46

plants lose water through their stomato. stomata remain closed so that less water vapour can be lost. The water evaporation will increase during the day due to the higher temperatures and drier conditions so closing them will reduce the water loss.
trapping water vapour close to the surface will reduce the difference in water molecules between the inside and the outside of the leaf. this will slow down the water loss from the plant

Question 47

During digestion what happens to large molecules

Answer 47

Large molecules are broken down into smaller molecules by digestive enzymes where they can then be absorbed into the blood stream

Question 48

Name the enzymes used n the digestive system and outline there use

Answer 48

Lipase - Breaks down Lipids (fats) into fatty acids and glyceral, Is made in the Pancreas and Small Intestine and works in the small intestine

Protease - Breaks down Proteins into amino acids, is made in the stomach, Pancreas and small intestine and works in the stomach and small intestine

Amalyse - Breaks down starch into sugars, is made in the slivary glands, pancreas and small intestine and works in the mouth and small intestine

Question 49

What changes occur in the thorax when a person breathes in

Answer 49

• the ribs move upwards and outwards
• the diaphragm flattens
• with the increase in volume in the thorax, the air pressure is lowered
• the pressure is now lower than the air pressure
• so air moves into the lungs passively