🌿 Grade 9 Science · Biology

Samacheer Class 9 Science - Organ Systems in Animals

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12 Sections
26 Questions

Complete Grade 9 Science questions and answers for Organ Systems in Animals. Click any question to expand the answer.

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📋 Sections in this chapter
I. Choose the Correct AnswerII. Fill in the BlanksIII. State Whether True or FalseIV. Match the FollowingV. Differentiate the FollowingVI. Answer BrieflyVII. Answer in DetailVIII. Assertion and Reason QuestionsIX. Higher Order Thinking SkillsX. Identify Female Reproductive PartsIntext ActivitiesActivity – 1
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1I. Choose the Correct Answer8 questions

Q.1Which is not a salivary gland?
✓ Answer
  • (a) Sublingual
  • (b) Lachrymal
  • (c) Submaxillary
  • (d) Parotid

Answer:
(b) Lachrymal

Lachrymal gland produces tears.

Q.2Stomach mainly digests
✓ Answer
  • (a) carbohydrates
  • (b) proteins
  • (c) fats
  • (d) sucrose

Answer:
(b) proteins


Q.3Entry of food into trachea is prevented by
✓ Answer
  • (a) Epiglottis
  • (b) Glottis
  • (c) Hard palate
  • (d) Soft palate

Answer:
(a) Epiglottis


Q.4Bile helps digestion of
✓ Answer
  • (a) proteins
  • (b) sugar
  • (c) fats
  • (d) carbohydrates

Answer:
(c) fats


Q.5Structural and functional unit of kidney is
✓ Answer
  • (a) villi
  • (b) liver
  • (c) nephron
  • (d) ureter

Answer:
(c) nephron


Q.6Which is not present in sweat?
✓ Answer
  • (a) Urea
  • (b) Protein
  • (c) Water
  • (d) Salt

Answer:
(b) Protein


Q.7Common passage for urine and sperms in male is
✓ Answer
  • (a) ureter
  • (b) urethra
  • (c) vas deferens
  • (d) scrotum

Answer:
(b) urethra

Correction made:
Original answer incorrectly marked vas deferens.

Q.8Which is not part of female reproductive system?
✓ Answer
  • (a) Ovary
  • (b) Uterus
  • (c) Testes
  • (d) Fallopian tube

Answer:
(c) Testes



2II. Fill in the Blanks0 questions
  • Opening of stomach into intestine is called pylorus.
  • Organ helping in mixing food with saliva is tongue.
  • Bile secreted by liver is stored in gall bladder.
  • Longest part of alimentary canal is ileum.
  • Normal human body temperature is about 37°C.
  • Largest cell in female body is ovum.


3III. State Whether True or False3 questions

If false, correct the statement.


Q.1Nitric acid in stomach kills microorganisms.
✓ Answer

Answer: False

Correct Statement:
Hydrochloric acid in stomach kills microorganisms.


Q.2Proteins are broken into amino acids during digestion.
✓ Answer

Answer: True


Q.3Hormones are present in glomerular filtrate.
✓ Answer

Answer: False

Correct Statement:
Glomerular filtrate normally contains water, salts, glucose, amino acids and urea but not proteins and blood cells.

Correction made:
Hormones may be present in traces; textbook expectation focuses on absence of proteins and cells.


4IV. Match the Following0 questions
OrganElimination Product
SkinSweat
LungsCarbon dioxide
IntestineUndigested food
KidneysUrine


5V. Differentiate the Following0 questions

# (a) Excretion and Secretion

ExcretionSecretion
Removal of metabolic wastesRelease of useful substances
Removes harmful substancesHelps body functions
Example: UrineExample: Enzymes, hormones

# (b) Absorption and Assimilation

AbsorptionAssimilation
Nutrients enter blood from intestineNutrients utilized by cells
Occurs in small intestineOccurs in body tissues

# (c) Ingestion and Egestion

IngestionEgestion
Intake of foodRemoval of undigested food
Beginning of digestionEnd of digestion

# (d) Diphyodont and Heterodont

DiphyodontHeterodont
Two sets of teethDifferent types of teeth
Milk teeth and permanent teethIncisors, canines, premolars, molars

# (e) Incisors and Canines

IncisorsCanines
Cutting and bitingTearing and piercing
8 in adults4 in adults


6VI. Answer Briefly6 questions

Q.1How Small Intestine Absorbs Food
✓ Answer

Answer:

Ileum contains millions of finger-like villi.

Each villus contains:

  • blood capillaries
  • lacteals

These absorb digested nutrients efficiently.


Q.2Why Do We Sweat?
✓ Answer

Answer:

Sweat cools body by evaporation.

Sweat contains:

  • water
  • salts
  • urea

Evaporation lowers body temperature.


Q.3Functions of Kidney
✓ Answer

Answer:

  • Maintains water and salt balance
  • Regulates pH of blood
  • Removes nitrogenous wastes
  • Maintains osmotic balance

Q.4What is Micturition?
✓ Answer

Answer:

Expulsion of urine from urinary bladder through urethra is called micturition.


Q.5Types of Human Teeth and Functions
✓ Answer
TeethFunction
IncisorsCutting
CaninesTearing
PremolarsCrushing
MolarsGrinding

Q.6Structure of Nephron
✓ Answer

Answer:

Nephron is structural and functional unit of kidney.


Parts of Nephron

  • Bowman’s capsule
  • Glomerulus
  • Proximal convoluted tubule
  • Loop of Henle
  • Distal convoluted tubule
  • Collecting duct

Blood Supply

  • Afferent arteriole enters glomerulus
  • Efferent arteriole leaves glomerulus


7VII. Answer in Detail2 questions

Q.1Alimentary Canal of Human
✓ Answer

# Parts of Alimentary Canal

  • Mouth
  • Buccal cavity
  • Pharynx
  • Oesophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus

# Mouth and Buccal Cavity

  • Teeth chew food
  • Tongue mixes saliva

# Teeth

Humans are:

  • Diphyodont
  • Thecodont
  • Heterodont

Dental Formula

$$\frac{2\ 1\ 2\ 3}{2\ 1\ 2\ 3} \times 2 = 32$$

# Salivary Glands

  • Parotid
  • Sublingual
  • Submandibular

# Oesophagus

Food moves by:

Peristalsis


# Stomach

  • J-shaped muscular organ
  • Digests proteins
  • Contains gastric juice and HCl

# Small Intestine

Parts:

  • Duodenum
  • Jejunum
  • Ileum

Main site for:

  • digestion
  • absorption

# Liver

Largest gland.

Produces bile.


# Pancreas

Produces digestive enzymes and hormones.


# Large Intestine

Absorbs water and forms faeces.

Parts:

  • Caecum
  • Colon
  • Rectum

Q.2Structure of Kidney and Urine Formation
✓ Answer

# Structure of Kidney

  • Bean-shaped organs
  • Located on either side of vertebral column
  • Right kidney slightly lower

Internal Structure

Cortex

Outer region

Medulla

Inner region

Contains renal pyramids.


Hilum

Entry point for:

  • blood vessels
  • nerves
  • ureter

# Steps in Urine Formation


# (i) Glomerular Filtration

Blood filtered in glomerulus.

Filtrate enters Bowman’s capsule.


# (ii) Tubular Reabsorption

Useful substances reabsorbed:

  • glucose
  • amino acids
  • water
  • salts

# (iii) Tubular Secretion

Waste ions secreted into tubule.

Final urine formed.


# Path of Urine

$$Kidney \rightarrow Ureter \rightarrow Urinary\ bladder \rightarrow Urethra$$


8VIII. Assertion and Reason Questions2 questions

Q.1Question 1
✓ Answer

Assertion: Urea is excreted through kidneys.
Reason: Urea is toxic.

Answer:
(a) Both are true and reason correctly explains assertion.


Q.2Question 2
✓ Answer

Assertion: Gonads perform dual functions.
Reason: Gonads are primary sex organs.

Answer:
(a) Both are true and reason correctly explains assertion.



9IX. Higher Order Thinking Skills5 questions

Q.1If Pepsin is Absent
✓ Answer

Answer:

Protein digestion into peptides will be affected.


Q.2Blood Vessels of Malpighian Corpuscle
✓ Answer
VesselFunction
Afferent arterioleEnters glomerulus
Efferent arterioleLeaves glomerulus

Q.3Importance of Urine Analysis
✓ Answer

Answer:

Helps diagnose:

  • Diabetes
  • Kidney disorders
  • Liver diseases
  • Urinary infections

Q.4Why Drink Plenty of Water?
✓ Answer

Answer:

Water helps:

  • Maintain hydration
  • Regulate body temperature
  • Kidney function
  • Remove wastes

Q.5Why Sweat Glands on Palms and Soles?
✓ Answer

Answer:

They help:

  • improve grip
  • prevent slipping
  • respond to emotional stress


10X. Identify Female Reproductive Parts0 questions
LabelPart
1Fallopian tube
2Ovary
3Cervix
4Uterus
5Vagina


11Intext Activities0 questions


12Activity – 10 questions

Teeth and Food Habits


# Carnivores (Lion)

Teeth Features

  • Sharp canines
  • Sharp molars
  • Used for tearing flesh

# Herbivores (Buffalo)

Teeth Features

  • Broad molars
  • Used for grinding plants

# Important Summary


Digestion

Breakdown of food into simple substances.


Absorption

Occurs in ileum through villi.


Excretion

Removal of nitrogenous wastes.


Kidney

Main excretory organ.


Nephron

Structural and functional unit of kidney.


Micturition

Expulsion of urine.


Human Teeth

  • Diphyodont
  • Thecodont
  • Heterodont

Salivary Glands

  • Parotid
  • Sublingual
  • Submandibular

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