Chapter 8 Transport in Animals

Question 1

What is the need for specialised transport systems in animals?

Answer 1

• metabolic demands are HIGH
• SA:V ratio is LOW
• molecules (like hormones) need transporting from where they are produced to where they are needed
• food, digested - needs transporting to cells (cells metabolism)
• waste products of metabolism - removed from cells - transported to excretory organs

Question 2

Types of circulatory systems (2)?

Answer 2

OPEN and CLOSED

Question 3

3 KEY features of a MASS TRANSPORT SYSTEM?

Answer 3

(1) liquid transport medium (circulates around systems)

(2) vessels (carrying transport medium)

(3) pumping mechanism - to move the transport medium

Question 4

OPEN circulatory systems??

Answer 4

• transport medium pumped straight from the heart to body cavity (HAEMOCOEL)
• transport medium is under LOW pressure
• comes into direct contact with tissues and cells
  (exchange takes place here)
• returns to the heart through an open-ended vessel

Question 5

OPEN circulatory systems in invertebrates??

Answer 5

• gas exchange through the tracheal system
• transport medium - haemolymph
  (only carries food and nitrogenous waste)
• body cavity is split by a membrane
• the heart extends along the length of the thorax and abdomen
• haemolymph circulates but a steep diffusion gradient CANNOT be maintained for efficient diffusion