أكاديميا - كولنز معاجم الجيب العلمية - البيولوجيا انكليزي - فرنسي - عربي الحرف ١_ r

Academia - Collins Scientific Pocket Dictionaries - Biology
English - French - Arabic Letter 1_ R


radical
radical f

The embryonic root of a seed plant is the first structure that emerges from the seed during germination
. see germination and seed. germination


radio
radius m

As a lesson. Anterior bones of the lower part of the front limbs of quadrupeds. In humans, it is the shorter of the two forearm bones. See endoskeleton.


receptor (or sense organ)
receiver m.

A receptor (or sensory organ). Specialized fabric at
The animal detects stimuli coming from the environment, and sends nerve impulses through the nervous system that lead to the necessary responses. See incom, backcross, and monohybrid inheritance
. plate dominance


recessive
accessif

Recessive. One of the pair of anti-alleles is expressed only with a homozygous phenotype. It is the opposite of dominant. See incom, backcross, monohybrid inheritance, and plate inheritance


rectum
rectum m

Rectum. The last part of the intestine at
In vertebrates, faeces accumulate before being excreted through the anus or cloaca.
See digestion.


red blood cell (or red blood corpuscle or erythrocyte)

globule m rouge. erythrocyte m. hematie f

Red blood cell (or erythrocyte). The most numerous cells in the blood of a vertebrate animal. It is responsible for transporting oxygen from the lungs to the tissues. In humans, bones are made in the brain in the form of concave-sided discs without nuclei.

Red blood cells contain hemoglobin, which combines with oxygen when blood passes through the lungs and forms a compound called oxyhaemoglobin. In tissues, this unstable compound breaks down and releases oxygen into the cells.

Hemoglobin + oxygen
Lungs tissue
oxyhemoglobin

A lack of red blood cells is called paleness or anemia
Blood anemia.


reflex action
reflexe m

Reflex action. (or reflexive). A rapid, involuntary response to a stimulus that occurs in most animals and vertebrates, and is caused by the spinal cord. Reflexes can be important in protecting animals from injury, such as pulling a limb away from a hot object.

Sensory nerve cell
Future pain in the skin
cell
Motor nervous
muscle (active)
Spinal cord section
Synapse

The structures related to reflex actions and the nerve impulses responsible for them form a reflex arc that begins to work when a nerve impulse is released at a receptor. The impulse is transmitted along a sensory neuron to the spinal cord, where it crosses a synapse. motor neurone to a synapse. When the reflex arc works, nerve impulses are also sent from the spinal cord to the brain. Thus, although the response begins from the spinal cord, it is through the brain that the animal realizes what is happening. See neurones.

Hot body
Hand pull
Nerve impulse
Nervous impulse
Spinal cord
Nerve impulse
Brain (pain is felt through...
A fraction of a second of pulling the hand).