Control and Coordination – Lecture Review

Flashcards covering stimuli, nervous and endocrine systems, brain parts, reflexes, plant tropisms, plant hormones, human hormones, diabetes, and feedback mechanisms.

What is a stimulus in biology?

A change in the environment (e.g., light, heat, sound) that elicits a response from an organism.

Which two main systems bring about control and coordination in animals?

The Nervous System and the Endocrine System.

Name the three structural parts of the human nervous system.

Brain, Spinal Cord, and a network of Nerves.

List two key functions of the nervous system.

(i) Receive information from the environment, (ii) Control voluntary muscular activities such as running or writing. (Other valid answers: enable thinking/memory, regulate involuntary actions.)

What are receptors?

Specialized nerve-cell tips that detect information from the environment and are located in sense organs.

Which receptors are found in the ear and what are their roles?

Phonoreceptors for hearing and receptors for maintaining body balance (vestibular).

Which receptors are located in the eyes and what do they detect?

Photoreceptors, which detect light for vision.

What type of receptors are present in the skin and what do they sense?

Thermoreceptors, which sense temperature (hot or cold), and touch receptors.

Which receptors in the nose are responsible for smell?

Olfactory receptors.

Which receptors on the tongue detect taste?

Gustatory receptors.

What is the structural and functional unit of the nervous system?

The neuron.

What is the role of dendrites in a neuron?

They receive information from other cells or the environment.

What does the cell body (soma) of a neuron do?

Transmits the received information as an electrical impulse.

What is the axon?

The longest fiber of a neuron that carries impulses from the cell body to the next neuron’s dendrite.

Define synapse.

The gap between the axon terminal of one neuron and the dendrite of another where an electrical signal converts to a chemical signal.

What is a reflex action?

A quick, sudden, and immediate response of the body to a stimulus.

Give one everyday example of a reflex action.

Withdrawing your hand after touching a hot object (also: mouth watering on smelling favorite food).

What is a reflex arc?

The pathway taken by nerve impulses during a reflex action.

Name the three main types of responses in humans.

Voluntary actions, Involuntary actions, Reflex actions.

Which part of the brain controls voluntary actions?

The forebrain (specifically the cerebrum).

Which brain regions control most involuntary actions like heartbeat and breathing?

The midbrain and hindbrain (medulla and pons).

Which part of the nervous system governs reflex actions?

The spinal cord.

Why are reflex actions essential?

They enable rapid responses to potentially harmful stimuli, preventing injury.

What are the two main divisions of the human nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS).

List the three major parts of the brain.

Forebrain, Midbrain, Hindbrain.

State one primary function of the forebrain (cerebrum).

Thinking, memory storage, or control of voluntary actions.

Give one function of the midbrain.

Controls involuntary actions, adjusts pupil size, and coordinates reflex movements of head and neck.

What does the cerebellum regulate?

Posture, balance, and precision of voluntary actions (e.g., picking up a pen).

Which hindbrain structure controls blood pressure and vomiting?

The medulla.

What is the protective covering of the brain called?

The cranium (skull) along with cerebrospinal fluid acting as a shock absorber.

How is the spinal cord protected?

It is enclosed within the vertebral column.

State one limitation of electrical (nervous) communication.

Impulses reach only cells connected by nervous tissue, and neurons need time to reset before a new impulse.

Do plants possess a nervous system?

No, plants coordinate via chemical and electrical signals, not nerves.

What is an example of plant movement independent of growth?

Drooping of ‘touch-me-not’ leaves immediately after touch.

Define phototropism.

Directional growth of a plant part toward light.

What is hydrotropism?

Directional growth toward water.

Which plant movement involves growth of a pollen tube toward an ovule?

Chemotropism.

Name the hormone synthesized at shoot tips that promotes cell elongation and phototropism.

Auxin.

Which plant hormone promotes stem elongation?

Gibberellin.

Which plant hormone promotes cell division, especially in fruits and seeds?

Cytokinin.

Which plant hormone inhibits growth and causes wilting under stress?

Abscisic acid (ABA).

What is a hormone in animals?

A chemical messenger secreted into the blood by endocrine glands to regulate body activities.

Which hormone from the pituitary gland promotes body height increase?

Growth hormone.

Why is iodised salt important in the diet?

Iodine is required for thyroxine synthesis in the thyroid gland, which regulates metabolism; deficiency causes goiter.

Which hormone readies the body for emergency situations, and where is it produced?

Adrenalin from the adrenal glands.

Name the hormone that controls blood sugar levels and the gland that secretes it.

Insulin, secreted by the pancreas.

Which hormone induces sperm production and male secondary sexual characteristics?

Testosterone from the testes.

Which hormone governs female secondary sexual characteristics and egg production?

Estrogen from the ovaries.

What is diabetes mellitus caused by?

Deficiency or ineffective use of insulin leading to high blood sugar.

How is diabetes commonly treated?

By injections or administration of insulin.

What is the purpose of a hormonal feedback mechanism?

To ensure hormones are secreted in the correct amount and at the appropriate time, preventing harmful excesses or deficiencies.