The central nervous system is divided into two parts: the brain and the spinal cord. The average adult human brain weighs 1.3 to 1.4 kg (approximately 3 pounds). The brain contains about 100 billion nerve cells and trillons of "support cells" called glia. The spinal cord is about 43 cm long in adult women and 45 cm long in adult men and weighs about 35-40 grams. The vertebral column, the collection of bones (back bone) that houses the spinal cord, is about 70 cm long. Therefore, the spinal cord is much shorter than the vertebral column.
The peripheral nervous system is divided into two major parts: the somatic nervous system and the autonomic nervous system.
The following table shows how the nervous system can be divided. The bottom row of the table contains the names of specific areas within the brain.
divendres, 22 de maig del 2009
dilluns, 30 de març del 2009
examen tema1
1. Explica per què es considera la cèl·lula la unitat fonamental dels éssers vius
Per què tots els éssers vius estan formats per cèl·lules i son indispensables per la vida al mon.
2. Escriu el nom dels orgànuls i de les parts de les cèl·lules eucariotes que es corresponen amb les funcions proposades
Digestió ..................Lysosomes................
Locomoció centrosome and cilia and flagella
Magatzem de nutrients ............... ........................
Fotosíntesi .................chloroplast..................
Síntesi de proteïnes .............ribosomes........................
Suport de la cèl·lula ..................... ..................
3. Fes una llista dels aparells i sistemes que formen el cos humà. Quines són els tres funcions vitals dels éssers vius? Quins aparells i sistemes participen en cadascuna d'elles. ( contesta al full apart.)
Digestive apparatus, respiratory apparatus, circulatory appartatus, excretory apparatus, nervious system, endocrine system, reproductive apparatus, locomotion apparatus
4. Relaciona els termes següents (escriu a la dreta de la segona columna què són):
/Bacterium (1
1) Cell / Heart (3
2) Tissue/ Onion Epidermis (2
3) Organ/ Red blood cell (1
4) Apparatus (organ system)/ A cat (5
5) Organism/ Nervous system (4
/ A potato plant (5
5. Indica si són veritables (V) o falses (F) les afirmacions següents.
The bigger animals have bigger cells than the smaller animals. V
There are no organisms made up of only one cell.: F
Bacteria have no nucleus:V
The shape of cells is very varied.:F
Vegetables are made up of procaryotic cells.:V
All eucaryotic cells have cell organelles.:V
Procaryotic cells have got a cytoplasm.:V
We usually measure the length of a cell in centimetres.:F
6. Explain the most important differences between the two main kinds of cells:
|
| Procaryotic cells | Eucaryotic cells |
| Size | big | small |
| Nucleus | not nucleus | yes have nucleus |
| Organelles | not organelles | have organelles |
8. Com es classifiquen els teixits del cos humà? Fes-ne un esquema o explica els quatre tipus bàsics de teixits i les seves diferents classes.
9. Label the illustration:
1-celular membrane
2-vesicles
3-golgi apparatus
4-ribosomes
5-endoplastic reticulum
9-nucleus
10-endoplastic reticulum
11-centrosome
12-cytoplasm
13-lysosomes
14-cilia and fagella
dijous, 5 de març del 2009
Tasques cn
4)- diferences:
Scientists believe that prokaryotic cells (in the form of bacteria) were the first life forms on earth. They are considered “primitive” and originated about 3.5 billion years ago. That's 2 billion years earlier than eukaryotic cells and billions of years before our earliest ancestors, the hominids.
Both have DNA as their genetic material (it’s DNA that tells cells what kind of cells they should be).
Both are covered by a cell membrane.
Both contain RNA.
Both are made from the same basic chemicals: carbohydrates, proteins, nucleic acid, minerals, fats and vitamins.
Both have ribosomes (the structures on which proteins are made).
Both regulate the flow of the nutrients and wastes that enter and leave them.
Both have similar basic metabolism (life processes) like photosynthesis and reproduction.
Both require a supply of energy.
Both are highly regulated by elaborate sensing systems ("chemical noses”) that make them aware of the reactions within them and the environment around them.
Scientists believe that prokaryotic cells (in the form of bacteria) were the first life forms on earth. They are considered “primitive” and originated about 3.5 billion years ago. That's 2 billion years earlier than eukaryotic cells and billions of years before our earliest ancestors, the hominids.
Both have DNA as their genetic material (it’s DNA that tells cells what kind of cells they should be).
Both are covered by a cell membrane.
Both contain RNA.
Both are made from the same basic chemicals: carbohydrates, proteins, nucleic acid, minerals, fats and vitamins.
Both have ribosomes (the structures on which proteins are made).
Both regulate the flow of the nutrients and wastes that enter and leave them.
Both have similar basic metabolism (life processes) like photosynthesis and reproduction.
Both require a supply of energy.
Both are highly regulated by elaborate sensing systems ("chemical noses”) that make them aware of the reactions within them and the environment around them.
Subscriure's a:
Missatges (Atom)
