Respiratory System

Question 1

Why do large organisms need transport systems?

Answer 1

SA:VOL ratio is too small to transport substances by diffusion because the distance is too large

Question 2

What are the adaptations of exchange surfaces?

Answer 2

Thin exchange surfaces for short diffusion pathway

large SA:VOL ratio

Maintain steep concentration gradient

Question 3

what are the adaptations of the lungs?

Answer 3

Large surface area - large amounts of alveoli

Good blood supply - maintains high concentration gradient

Short diffusion distance - alveoli and capillary are 1 cell thick

moist surface - gases dissolve and facilitate diffusion

Question 4

Explain the structure of the respiratory system?

Answer 4

Air is inhaled by mouth/nose and travels down the trachea

trachea branches into 2 smaller tubes called bronchi

brochi are divided into bronchioles which sends air to alveoli where it is exchanged into the blood

Lungs surrounded by pleural membrane

ribcage surrounded by intercostal muscles protects organs

Question 5

What are goblet cells?

Answer 5

secrete mucus to trap dust and microorganisms to prevent infection

Question 6

What are elastic fibres?

in lungs

Answer 6

Fibres that stretch and recoil when inhaling and exhaling

Question 7

what is smooth muscle?

In the lungs

Answer 7

control the diameter of airway by contracting or relaxing

Question 8

what is cartilage?

in the lungs

Answer 8

C shaped rings

provide strength and support

prevents airway from collapsing

Question 9

Describe inhalation

Answer 9

Diaphragm moves down and flattens

internal intercostal muscles contract and external relax

ribcage moves upwards and out

increased volume of thorax, decreased pressure so air enters lungs

Question 10

Describe exhalation

Answer 10

Diaphragm moves upwards

internal intercostal muscles relax and external contract

ribcage moves upwards and out

decreased volume of thorax, increased pressure so air pushed out lungs

Question 11

what is a spirometer?

Answer 11

Equipment used to investigate volume of air someone can breathe

Consists of chamber filled with oxygen that moves up or down when people breathe

a pen draws a spirometer trace

Question 12

What is tidal volume?

Answer 12

the volume of air in each breath

Question 13

what is vital capacity?

Answer 13

the maximum volume of air that a person can exhale form their lungs after a maximum inhalation

Question 14

what is breathing rate?

Answer 14

the number of breathes per minute

Question 15

what is oxygen consumption?

Answer 15

the volume of oxygen used by the body

Question 16

Why does the volume of the chamber decrease?

Answer 16

Spirometer contains soda lime which absorbs CO2 breathed out.

Oxygen in the chamber would be consumed by the person

Question 17

Describe the structure of the gill

Answer 17

Each gill made of several gill filaments stacked on top of each other

Gill filaments covered in lamellae - increases surface area

Gill filaments have thin cell walls - short diffusion path

Question 18

What is a counter current system?

Answer 18

Blood in the capillaries flow in opposite direction to the water

Maintain oxygen concentration gradient

Question 19

How are fish gills ventilated?

Answer 19

When fish opens it mouth, the buccal cavity lowers, increasing mouths volume

pressure decreases, causing water to enter mouth into buccal cavity

fish closes mouth, buccal cavity moves up, volume reduces

pressure increases forcing water through the gill filaments

water moves over gill filaments and increases pressure, operculum is forced open and water leaves

Question 20

Describe ventilation in insects

Answer 20

Air enter through pores called spiracles

Air moves down the trachea, which branches into tracheoles

walls of tracheoles are thin - short diffusion path

Rhythmic abdominal movements push air into and out of the spiracles - maintain steep concentration gradient