cells

What procaryotic and eucaryotic cells have in common?
1.DNA as genetic material.
2.Ribosomes synthesize proteins.
3.Enzymes that catalyse metabolic reactions.
4.Similar metabolic pathways.
5.Membranes with similar or identical components and orgamizations.

What are the differences?
Procaryotic cells:
-No nucleus
-No membrane covered organelles.
-Circular DNA.
-Most referred to as bacteria.
-Has ribosomes.

Eucaryotic cells:
-Has a nucleus.
-Has membrane covered organelles.
-Linear DNA
-Are all other types of cells.
-Has organelles and organelles parts like chloroplast and mitochondria.

circulatory system

The function of the circulatory system are:

-Carry oxygen from the lungs to the tissues and carbondioxide from the tissues to the lungs.

-Help in fighting infections.

-Helps to maintain the Ph of the blood.

-Parts of the circulatory system:

*Heart: is a muscular organ responsible for pumping blood through the blood vessels by rhythmic contractions.

*Blood vessels:

-Arteries: carry the blood away from the heart.

-Capillaries: enable the actual exchange of water and chemicals between the blood and the tissues.

-Veins: carry blood from the capillaries back towards the heart.

*Blood: is a specialized bodily fluid that delivers necessary substances to the body's cells and transports waste products away from those same cells.

respiratory system

Respiratory system

The function of the respiratory system is to allow gas exchange.

Nasal passage: is the sinus cavitie of the human body.

Oral cavity: is the mouth.

Pharynx: conected the oral cavity with the larynx.

Larynx: involved in protection of the trachea and sound production.

Trachea: is a common term for an airway through which respiratory air passes in organisms.

Bronchus: is a passage of airway in the respiratory tract that conducts air into the lungs.

Lung: the lungs transports oxygen into the bloodstream and to take carbon dioxide out of the bloodstream.

Heart: pumps oxygenated blood to all parts of the body. Pumps deoxygenated blood to the lungs.

Ribs: protects the internal organs from damage. The rib cage expands during respiration.

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Digestive system

The digestive tract (also known as the alimentary canal) is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. The major function of the GI tract are ingestion, digestion, absorption, and defecation. The GI tract differs substantially from animal to animal. Some animals have multi-chambered stomachs, while some animals' stomachs contain a single chamber. In a normal human adult male, the GI tract is approximately 6.5 meters (20 feet) long and consists of the upper and lower GI tracts. The tract may also be divided into foregut, midgut, and hindgut, reflecting the embryological origin of each segment of the tract.

Parts of the digestive system: mouth and salivary glands, esophagus, liver, gallblader, duodenum, ascendum colon, ileum, cecum,appendix, anus, stomach, pancreas, jejunum, sigmoid colon and rectum

THE EYE AND EAR

EYE

Vitreous gel: is a thick, colorless, gel-like fluid that fills the large space in the middle of the eye. It helps the eyeball maintain its shape.

Optic nerve: transmits visual information from the retina to the brain.

Macula: is an oval-shaped highly pigmented yellow spot near the center of the retina.

Fovea: is responsible for sharp central vision.

Retina: is a light sensitive tissue lining the inner surface of the eye.

Iris: by contraction and dilatation, regulates the entrance of light into the eye.

Cornea: is a lens that helps to shield the rest of the eye from germs, drust...

Pupil: it regulates the amount of light that enters the eye.

Lens: it reflects the light.

EAR

Auricle (pinna): it prottect the inner ear.

Auditory canal: it carries the vibration from outer ear to the inner ear.

Semicircular canals: it helps maintain balance.

Cochlea: it moves in response to the vibrations coming from the middle ear.

Incus (anvil): it transmits the sound vibrations from the malleus to the stapes.

Stapes (stirrup): it transmits the sound vibrations from the incus to the membrane of the inner ear inside the fenestra ovalis.

Malleus (hammer): it transmits the sound vibrations from the eardrum to the incus.

Tympanic membrane (eardrum): it transmits sound from the air to the ossicles inside the middle ear.

The central nervous system: (CNS) is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of multicellular organisms. In vertebrates, the central nervous system is enclosed in the meninges. It contains the majority of the nervous system and consists of the brain and the spinal cord. Together with the peripheral nervous system it has a fundamental role in the control of behavior. The CNS is contained within the dorsal cavity, with the brain in the cranial cavity and the spinal cord in the spinal cavity. The brain is protected by the skull, while the spinal cord is protected by the vertebrae.

Function: Since the strong theoretical influence of cybernetics in the fifties, the central nervous system is conceived as a system devoted to information processing, where an appropriate motor output is computed as a response to a sensory input. Yet, many threads of research suggest that motor activity exists well before the maturation of the sensory systems, and that then the senses only influence behavior without dictating it.

The peripheral nervous system (PNS) resides or extends outside the central nervous system (CNS), which consists of the brain and spinal cord.[1] The main function of the PNS is to connect the CNS to the limbs and organs. Unlike the central nervous system, the PNS is not protected by bone or by the blood-brain barrier, leaving it exposed to toxins and mechanical injuries. The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system.

Parts: cerebellum, brain stem, hypothalamus, thalamus, limbic system, hippocampus, basal ganglia and midbrain.