Q11 of 38 Page 93

i) What are the structural and functional units of kidney?

ii) Arrange the organs of the human excretory system in the correct order, based on the passage of urine.


Ureter, Urethra, Kidney, Urinary bladder


i) The structural and functional unit of kidney is nephron. The nephrons are responsible for forming the urine. A nephron is composed of Glomerulus and renal tubules.


ii) Kidney, Ureters, Urinary bladder, Urethra. Urine produced by nephrons in the kidney travel down through the ureters to the urinary bladder. The urinary bladder can expand for storage or collapse when empty. The urine is expelled outside the body through the urethra.


More from this chapter

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9

Which blood cells are without nuclei? What is the advantage of this condition?

 10

Name the protein and the blood-cells responsible for the clotting of blood.

 12

Observe the following flow-chart depicting blood-circulation in mammals.


Pick out the correct blood vessels A, B, C, D from the following:


i) Pulmonary veins


ii) Venacava


C. Pulmonary artery


D. Aorta


Among the P,Q,R and S samples, identify the correct match from the following


a) P & Q = Oxygenated and R& S = Deoxygenated


b) P & Q = Deoxygenated and R& S = oxygenated


c) All are Oxygenated


d) All are Deoxygenated


 13

Study the following passage:

Most of the vertebrates have jaws with teeth. The mode of arrangement of teeth on the jaws is called dentition.


The various types of teeth seen in mammals are incisors(I) canines (C) premolars (P) and molars (M). They are used for biting, tearing, chewing and grinding respectively.


Canines, the tearing teeth are well-developed in carnivores and ill-developed or absent in herbivores.


Now answer the following questions:


i) In frogs, all the teeth in the upper jaw look alike, whereas in human beings they are different. The type of dentition in man can be called__________.


a) Homodont


b) Isodont


c) Heterodont


d) Acrodont


ii) The dental formula of a mammal is written as ICPM =2023/1023. The teeth missing in it are _________ .


a) incisors


b) b) canines


c) c) premolars


d) d) molars