The primary xylem and primary phloem tissues are pushed inward into the] pith and outwards respectively by the continuous production of secondary tissues cut I off by the cambium ring. The primary xylem is gradually pushed inward and is found at the centre of the axis; whereas‚ the primary phloem‚ being soft in nature‚ gets completely crushed. These activities in the stelar region exert a great pressure outwardly. The cortex cells‚ the pericycle and the epidermis divide anticlinally to cope
Premium Plant anatomy Phloem Epidermis
The evolution of plants has resulted in increasing levels of complexity‚ from the earliest algal mats‚ through bryophytes‚ lycopods‚ ferns to the complex gymnosperms and angiosperms of today. While the groups which appeared earlier continue to thrive‚ especially in the environments in which they evolved‚ each new grade of organisation has eventually become more "successful" than its predecessors by most measures. Probably an algal scum formed on land 1‚200 million years ago. In the Ordovician period
Premium Plant Fern Xylem
type of reproduction that does not involve the union of gametes. | |two parents. | | |2. New plants are produced from seeds. |2. New individual is produced from a single parent. | Q3. Differentiate between binary fusion and budding. Draw a well-labeled diagram showing both
Premium Seed Reproduction Flower
Thursday‚ January 30‚ 2014 Nervous Tissue ! Anatomy & Physiology - Overall Purpose of the Nervous System ! • To keep controlled conditions within limits that maintain life health and homeostasis ! - Regulates body activities by responding via nerve impulses‚ works with the endocrine system which responds by releasing hormones ! • Responsible for our behavior‚ memories‚ and movements ! • Neurology : branch of medicine that deals with normal functioning and disorders of the nervous system
Premium Action potential Neuron
Plants Desert Baobab Tree The baobab tree is the iconic tree of the African Sahara. It is readily recognized by its enormous trunk and‚ by comparison‚ scrawny stems and twigs. It is the source of many legends among the tribes of the area‚ and is also a rich source of traditional medicine. In a land where rainfall is limited and it is rare to find even tiny bushes‚ the gigantic baobab tree thrives. It is able to do so due to a number of unique adaptations that it has perfected over the course
Premium Cactus
from the aerial parts of plants‚ especially leaves but also stems‚ flowers and roots. Leaf surfaces are dotted with openings called stomates that are bordered by guard cells. Collectively‚ the structures are called stomata.[1] Leaf transpiration occurs through stomata‚ and can be as a necessary "cost" associated with many processes such as the opening of the pistil and allowing the diffusion of carbon dioxide gas from the air for photosynthesis. Transpiration also cools plants and enables mass flow
Premium Transpiration Water Plant physiology
Human Growth Hormone" As we grow‚ our body faces a major physical change which consists of both positive and negative effects which directly affects us on our living. Growth of human hormones is one of the most important factors which devalue on as we become older. The process of aging is directly related to human growth‚ which is created by a pituitary gland‚ the master gland of the endocrine system. The human growth hormones play a vital role in the development of our body tissues‚ bones and
Premium Growth hormone Immune system
the plant. This means that guard cells on the stomata are generally inactive. 3. An increased number of stomata‚ that can be on either side of leaves. 4. A less rigid structure: water pressure supports them. 5. Flat leaves on surface plants for flotation. 6. Air sacs for flotation. 7. Smaller roots: water can diffuse directly into leaves. 8. Feathery roots: no need to support the plant. 9. Specialized roots able to take in oxygen. Floating All floating plants
Premium Photosynthesis Plant Plant morphology
Role of mycorrhizas in the mineral nutrition of host plants Mycorrhizas are very important in the uptake of nutrients such as P‚ N‚ K‚ Cu‚ Zn and Ca by plants especially in soils low in these nutrients. Since P is the most limiting nutrient in tropical soils‚ mycorrhizas are vital for improving P nutrition particularly for cultivated plants. External hyphae can absorb and translocate P to the host from soil outside the root depletion zone. The thin mycorrhizal hyphae (2-4 μm in diameter) are able
Premium Plant Fungus Soil
metabolism‚ have targeted two chemically identified neuronal types within the ARC: anorexigenic pro-opiomelanocortin (POMC) neurons and orexigenic neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons. The melanocortin α-melanocyte stimulating hormone (α-MSH‚ a biologically active peptide produced in POMC neurons) serves as an agonist‚ whereas AgRP is an inverse agonist at the anorectic melanocortin receptors (MC3R and MC4R) in the central nervous system. NPY elicits its physiological effects via
Premium Nervous system Hypothalamus