Cytokinins delay the senescence of plant organs by controlling protein synthesis and mobilisation of resources. This phenomenon is called the Richmond Lang effect. They help produce chloroplast in leaves. These are also called anti-ageing hormones.

Sympathetic nervous system stimulation causes vasoconstriction of most blood vessels, including those of the skeletal muscle.

In a neuron, a dendrite receives a signal from an axon terminal of a neuron through a synapse.

Limbic lobe of the brain governs the emotions and memory of an individual.

Kenneth Vivian Thimann is known for his studies of plant hormones, which were widely influential in agriculture and horticulture. He isolated and determined the structure of auxin, the first known plant hormone.

An auxin is manufactured primarily in the shoot tips (in leaf primordia and young leaves), in embryos, and in parts of developing flowers and seeds. Its transport from cell to cell, through the parenchyma surrounding the vascular tissues, requires the expenditure of ATP energy. IAA moves in one direction only, that is the movement is polar and, in this case, downward.

They activate the differentiation of non-vascular tissue in the shoot apex. They activate the differentiation of vascular tissue in the shoot apex and in calluses. They also initiate division of the vascular cambium in the spring and promote growth of vascular tissue in healing of wounds.

The epithalamus is a dorsal part of the diencephalon and connects the limbic system to other parts of the brain.

The cerebral cortex is the portion of the brain that provides remarkable distinctions between humans and other animals. It enables humans not only to receive and interpret all kinds of sensory information, such as color, odor, taste, and sound, but also to remember, analyze, interpret, make decisions, and performs a host of other higher brain functions.

The cerebral cortex plays a key role in memory, attention, perceptual awareness, thought, language and consciousness.

Natural auxin: It was first isolated from human urine by Kogl and Haagensmit. It was named as auxin-a. But later, Kogl obtained another auxin called auxin-b (auxentriolic acid) from corn germ oil and heteroauxin from human urine. Heteroauxin, also known as indole-3-acetic acid (IAA) is the best known natural auxin. Indole butyric acid is another natural auxin.

Gibberellins induces production of male flowers on genetically female plants.

The parasympathetic system is responsible for stimulation of "rest-and-digest" or feed and breed activities that occur when the body is at rest, especially after eating, including sexual arousal, salivation, lacrimation (tears), urination, digestion and defecation.

 It is found in the tissues where rapid growth is taking place like growing fruits, root tips and shoot buds. Chemically, cytokinins are purines derived from tRNA 3. They are also present in coconut water (liquid endosperm).  

Ependyma is the thin epithelium-like lining of the ventricular system of the brain and the central canal of the spinal cord. Ependyma is one of the four types of neuroglia in the central nervous system (CNS). It is involved in the production of cerebrospinal fluid (CSF).

A spinal nerve is a mixed nerve which carries motor, sensory and autonomic signals between the spinal cord and the body. There are 31 pairs of spinal nerves, one on each side of the human vertebral column.

A pseudounipolar neuron is a kind of sensory neuron in the peripheral nervous system. This neuron contains an axon that has split into two branches; one branch runs to the periphery and the other to the spinal cord.

The axolemma is the cell membrane surrounding an axon. It is responsible for maintaining the membrane potential of the neuron, and it contains ion channels through which ions can flow.

Gravitaxis is a response to the attraction due to gravity. The planktonic larvae of the king crab (Lithodes aequispinus) use a combination of positive phototaxis (movement towards the light) and negative gravitaxis (upward movement).

The pons is a section of the brain lying above the medulla oblongata. It plays important role in arousal, sleep, carrying sensory information between cerebrum and cerebellum, and helping control of autonomic functions.