Internal Structure of Plants and Animals | Jamb Biology

Jamb(UTME) tutorial on Internal Structure of Plants

Internal Structure of Flowering Plants

General Characteristics

1. The internal structure of flowering plants includes tissues specialized for support, transport, and photosynthesis.
2. Flowering plants have three main organs: roots, stems, and leaves.
3. These organs are composed of different tissues, including parenchyma, collenchyma, sclerenchyma, xylem, and phloem.
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Transverse Sections of Roots

4. The transverse section of a root shows a central vascular bundle surrounded by the cortex.
5. The outermost layer is the epidermis, which absorbs water and minerals.
6. Beneath the epidermis is the cortex, made of parenchyma cells for storage.
7. The endodermis, a single layer of cells, regulates the flow of water and minerals.
8. The vascular bundle contains xylem (water transport) and phloem (food transport).
9. Pericycle surrounds the vascular bundle and contributes to lateral root formation.
10. Xylem is star-shaped in dicot roots, while monocot roots have a circular arrangement.
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Transverse Sections of Stems

11. In stems, the epidermis forms the outer protective layer.
12. Beneath the epidermis lies the cortex, containing collenchyma and parenchyma for support and storage.
13. The vascular bundles, made up of xylem and phloem, are arranged in a ring in dicots and scattered in monocots.
14. Cambium is present in dicot stems for secondary growth, absent in monocots.
15. The pith, located at the center, consists of parenchyma cells for storage.
16. Sclerenchyma fibers in the stem provide additional strength.
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Transverse Sections of Leaves

17. The transverse section of a leaf shows three main layers: the upper epidermis, mesophyll, and lower epidermis.
18. The cuticle covers the epidermis to minimize water loss.
19. The mesophyll contains palisade cells (photosynthesis) and spongy cells (gas exchange).
20. Vascular bundles in the leaf consist of xylem (water transport) and phloem (food transport).
21. Stomata, primarily on the lower epidermis, regulate gas exchange and transpiration.
22. Monocot leaves have parallel venation, while dicot leaves have reticulate venation.
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Functions of Roots, Stems, and Leaves

Roots

23. Roots anchor plants to the soil.
24. They absorb water and nutrients through root hairs.
25. The vascular tissues transport absorbed water and minerals to other parts of the plant.
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Stems

26. Stems provide structural support to leaves, flowers, and fruits.
27. They transport water through xylem and nutrients through phloem.
28. Stems store food in some plants, such as potatoes and sugarcane.
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Leaves

29. Leaves are the primary site of photosynthesis.
30. They regulate transpiration through stomata.
31. Leaves store nutrients in some plants, such as spinach and cabbage.
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Supporting Tissues in Plants

Collenchyma

32. Collenchyma cells have thickened cell walls, providing flexibility and mechanical support.
33. These tissues are commonly found in stems, petioles, and leaf veins.
34. Collenchyma allows plants to withstand wind and mechanical stress.
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Sclerenchyma

35. Sclerenchyma cells have thick, lignified walls, making them rigid.
36. These cells are dead at maturity and provide structural support.
37. Sclerenchyma is found in seed coats, shells, and fibers.
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Xylem

38. Xylem conducts water and minerals from roots to other parts of the plant.
39. It consists of tracheids, vessels, xylem fibers, and parenchyma.
40. Xylem fibers provide additional strength and rigidity.
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Phloem

41. Phloem transports food from leaves to other parts of the plant.
42. It consists of sieve tubes, companion cells, phloem fibers, and phloem parenchyma.
43. Phloem fibers also contribute to structural support.
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Distribution of Supporting Tissues

In Roots

44. Collenchyma is absent in roots but present in stems and leaves.
45. Sclerenchyma is found in the pericycle of monocot roots.
46. Xylem and phloem are arranged in a radial pattern.
47. The vascular bundle is centrally located, surrounded by parenchyma for storage.
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In Stems

48. Collenchyma is located in the cortex, just beneath the epidermis.
49. Sclerenchyma surrounds vascular bundles, providing rigidity.
50. Vascular bundles are arranged in a ring in dicot stems.
51. Xylem and phloem are found within the vascular bundles.
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In Leaves

52. Collenchyma is found in midribs and veins.
53. Sclerenchyma supports vascular bundles in the veins.
54. Xylem is located on the upper side, and phloem is on the lower side of vascular bundles.
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Adaptations of Tissues to Functions

55. Xylem vessels are hollow and continuous for efficient water transport.
56. Phloem sieve tubes are perforated, allowing easy movement of food.
57. Collenchyma’s flexibility allows plants to bend without breaking.
58. Sclerenchyma’s rigidity helps plants stand upright.
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Comparing Monocot and Dicot Structures

59. Monocot roots have scattered vascular bundles, while dicot roots have radial bundles.
60. Monocot stems lack cambium and secondary growth; dicot stems have both.
61. Monocot leaves show parallel venation; dicot leaves have reticulate venation.
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Microscopic Features

62. Parenchyma cells are thin-walled and store nutrients.
63. Collenchyma cells have unevenly thickened walls for flexibility.
64. Sclerenchyma cells have thick, lignified walls for rigidity.
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Role of Supporting Tissues

65. Collenchyma strengthens young plant parts.
66. Sclerenchyma provides mechanical support in mature tissues.
67. Xylem supports tall plants by transporting water to the canopy.
68. Phloem fibers reinforce vascular bundles.
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Specialized Structures

69. The casparian strip in the endodermis of roots regulates water flow.
70. Cambium in dicot stems enables secondary growth.
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Functions of Specialized Tissues

71. Tracheids in xylem provide structural support and water conduction.
72. Companion cells in phloem help sieve tubes transport food efficiently.
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Growth and Development

73. Meristematic tissues divide to form new cells in roots, stems, and leaves.
74. The vascular cambium contributes to the thickness of dicot stems.
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Protective Structures

75. The epidermis prevents water loss and protects underlying tissues.
76. Stomata in leaves control gas exchange and water loss.
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Storage Functions

77. Parenchyma stores starch in roots like carrots.
78. Stems like sugarcane store sucrose for energy.
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79. Thickened sclerenchyma helps plants withstand strong winds.
80. Collenchyma aids in mechanical support during storms.
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Transport Mechanisms

81. Root pressure facilitates water movement in xylem.
82. Translocation of sugars occurs through phloem.
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Diversity in Vascular Systems

83. Woody plants have well-developed xylem for strength.
84. Herbaceous plants rely more on collenchyma for support.
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Importance of Supporting Tissues

85. Supporting tissues enable plants to grow taller and compete for sunlight.
86. They prevent plants from collapsing under their own weight.
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Comparative Analysis

87. Xylem is stronger than phloem due to lignin deposition.
88. Collenchyma provides flexibility, while sclerenchyma provides rigidity.
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Relevance to Photosynthesis

89. Palisade mesophyll in leaves maximizes photosynthesis.
90. Veins in leaves ensure efficient transport of water and nutrients.
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Stress Tolerance

91. Sclerenchyma fibers help plants survive mechanical stress.
92. Collenchyma allows young stems to bend without breaking.
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Anatomical Differences

93. Dicot stems have secondary growth; monocots do not.
94. Leaf venation is more intricate in dicots than monocots.
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Protective Layers

95. The cuticle on leaves reduces water loss.
96. Suberin in root endodermis prevents water backflow.
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Conclusion

97. Supporting tissues are vital for plant strength, transport, and survival.
98. Roots, stems, and leaves work together to support plant functions.
99. Xylem and phloem ensure efficient resource distribution.
100. Collenchyma and sclerenchyma provide the flexibility and rigidity needed for structural stability.
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Jamb(UTME) tutorial on Internal Structure of Animals

Internal Structure of a Mammal

General Characteristics

1. Mammals have a well-organized internal structure with specialized organs for various functions.
2. The internal organs are located in body cavities: the thoracic cavity (chest) and abdominal cavity.
3. Mammalian organs are arranged systematically to optimize physiological processes like digestion, reproduction, and excretion.
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Arrangement of Mammalian Internal Organs

Thoracic Cavity

4. The heart is centrally located in the thoracic cavity, protected by the ribcage.
5. The lungs are positioned on either side of the heart for gas exchange.
6. The trachea connects the nasal passage to the lungs, facilitating breathing.
7. The esophagus runs behind the trachea, connecting the mouth to the stomach.
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Abdominal Cavity

8. The stomach is on the left side of the upper abdomen, where food is digested.
9. The liver lies in the upper right abdomen, producing bile for digestion.
10. The intestines (small and large) occupy most of the abdominal cavity, responsible for nutrient absorption and waste formation.
11. The kidneys are located at the back of the abdominal cavity on either side of the spine, filtering blood.
12. The bladder, below the intestines, stores urine for excretion.
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Digestive System

Appearance and Position

13. The stomach is a muscular, J-shaped organ beneath the diaphragm.
14. The small intestine, long and coiled, is attached to the stomach and occupies the central abdomen.
15. The large intestine, wider and shorter, surrounds the small intestine.
16. The liver is a large, reddish-brown organ above the stomach.
17. The pancreas, located behind the stomach, produces digestive enzymes.
18. The esophagus is a tube-like structure connecting the mouth to the stomach.
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Functions

19. The stomach breaks down food using gastric juices.
20. The small intestine absorbs nutrients, while the large intestine absorbs water and forms feces.
21. The liver detoxifies substances and aids digestion by producing bile.
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Reproductive System

22. Male Reproductive Organs

22. The testes are located outside the abdominal cavity in the scrotum, producing sperm.
23. The vas deferens transports sperm from the testes to the urethra.
24. The prostate gland, near the bladder, secretes fluid that nourishes sperm.
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Female Reproductive Organs

25. The ovaries are small, almond-shaped organs in the lower abdomen, producing eggs.
26. The fallopian tubes transport eggs from the ovaries to the uterus.
27. The uterus is a pear-shaped organ where fetal development occurs.
28. The vagina, a muscular canal, connects the uterus to the external genitalia.
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Excretory System

Appearance and Position

29. The kidneys are bean-shaped organs located near the back of the abdominal cavity.
30. Ureters are thin tubes connecting the kidneys to the bladder.
31. The bladder is a hollow, muscular organ in the pelvic region.
32. The urethra extends from the bladder to the outside, allowing urine to exit the body.
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Functions

33. The kidneys filter blood to remove waste products and excess water.
34. Ureters transport urine from the kidneys to the bladder.
35. The bladder stores urine until it is excreted.
36. The urethra expels urine during urination.
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Key Relationships Between Organ Systems

Digestive and Excretory Systems

37. The liver detoxifies substances, and waste products are excreted by the kidneys.
38. Water absorbed in the intestines is crucial for kidney function.
39. The excretory system removes nitrogenous waste derived from protein digestion.
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Digestive and Reproductive Systems

40. Nutrients absorbed by the digestive system are vital for reproductive processes.
41. Pregnancy involves adjustments in digestive organ positions to accommodate the growing fetus.
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Summary of Organ Positions

42. The heart is the central organ of the circulatory system, protected by the ribcage.
43. The lungs surround the heart and play a key role in oxygenating blood.
44. The stomach lies beneath the diaphragm in the upper abdomen.
45. The liver is above the stomach, to the right.
46. The intestines are coiled and occupy most of the abdominal cavity.
47. The kidneys are located at the back of the abdomen, below the ribs.
48. The bladder is in the lower pelvis, below the intestines.
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Organ Functions and Integration

49. Each organ works in coordination with others to maintain homeostasis.
50. The arrangement of mammalian internal organs optimizes space and functionality, ensuring survival and reproduction.

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