biologia

Posted on Oct 23, 2023 in Biology

Blood composition:

  • Blood plasma: water with minerals (90%), nutrients (glucose, amino acids, vitamins…), waste products (urea, uric..), proteins and dissolved hormones.
  • Blood cells: Leukocytes or white blood cells, Erythrocytes or red blood cells ( contain hemoglobin, red pigments that carries oxygen from pulmonary alveoli to all the cells in our body), Thrombocytes or platelets.

Functions of the blood:

  • Transports nutrients and oxygen to all the cells and collects waste products produced by cell metabolism, carries hormones.
  • Contributes to the regulation of body temperature.
  • Plays a role in the fight against infections.

Blood vessels:

  • Arteries: these carry blood from the heart to other organs, get further away from the heart, they branch out and become thinner until they reach and enter the organs (arterioles).
  • Capillaries: exchange between blood and cells.
  • Veins: carry blood from tissues to the heart, venues which drain blood from capillaries, join together.


Heartbeat: performs a constant movement called heartbeat.

  • Heart rate: refers to the number of times the heart beats per unit of time.
  • Cardiac output: the volume of blood the heart pumps in one minute.

   1.Atrial systole: atriums contract and blood is propelled thought the opened atrioventricular valves into the ventricle 

   2. Ventricular systole: ventricles contract sigmoid valves opened and blood exits throught the pulmonary artery and the aorta 

   3. Diastole: the heart relaxes and sucks blood coming from veins 

Blood circuits: 

  • Systemic circuit: starts in the left ventricle and goes through the aorta, reaching all the tissues and organs exceptionalities the lungs, removes waste, it returns to the heart thong venules and cava veins.
  • Pulmonary circuit: it begins in the right ventricle from which the pulmonary artery, lung, pulmonary alveoli, blood goes into te left ventricle though the mitral valve.
  • Circulation is double, circulation is complete , circulation is closed


The excretory system: is the group of organs that facilitate the elimination of waste products by cells metabolism (Carbon dioxide, Urea and uric acid, toxic substances)

  • Liver: it eliminates products resulting from the destruction of hemoglobin. These products make up part of the bile, also eliminates a small quantity of cholesterol and certain toxic substances.
  • Respirator system: it removes CO2.
  • Sweat glands: sweat also releases certain waste products to the exterior.
  • Urinary system: eliminates waste products thought the urine.

Kidneys: External section, called the renal cortex, an internal section called renal medulla and a cavity called renal pelvis.The renal pelvis collects urine, a liquid formed in the renal cortex and medulla that contains waste products. Nephrons are the structural and functional units of the kidneys, responsible for filtering blood and forming urine.

  • Bowman’s capsule: the initial zone, inside is a capillary called the glomerus of Malpighi.
  • Convoluted tube: long twisted tube that has two parts (proximal and distal).
  • Loop of Henle: section located between the proximal convoluted tube and the distal one.


Cardiovascular health:

  • Do not smoke: increases the risk of arteriosclerosis, in the larger arteries.
  • Do not use too much salt in your food, increases the work rate of the heart.
  • Try to avoid stress because it increases blood pressure and can lead to certain cardiovascular diseases.
  • Exercise regular to increase your cardiac capacity and to reduce the chances of suffering from arteriosclerosis.

Health of the excretory system:

  • Drink water and other liquids, substances dissolved in the urine aren’t too concentrated, prevent the formation of kidney and urinary tract stones.
  • Don’t eat excessively salty foods, as this increases the concentration of uric and in the blood lead to the formation of stones.
  • Avoid toxic substances, alcohol, medications. This extra work for the organs can lead to serious illnesses.
  • Maintain a balance diet, exercise and go to the toilet every time you need to urine.

Dialysis: When the kidneys are unable to perform their function, it’s essential to eliminate waste products, blood is filtered artificially to eliminate waste and toxic products when the kidneys are unable to do the job adequately. Two types (hemodialysis and peritoneal dialysis)



  • URETERS: start in the kidneys and end in the bladder an elastic bag where urine is collected before being expulsed to the exterior 
  • URETHRA: is a duct that is connected with the exterior. A man’s urethra is connected with the reproductive system and can also realed semen 

Urine: is a liquid obtained from blood composed of water, minerals and diverse waste products.

  •  Glomerular filtration: this consists of the passage of certain substances from the blood contained in the Malpighian glomerulus to the interior of Bowman’s capsule. As a result, water and the majority of the molecules that are in the blood plasma are filtered, including waste products (urea, uric acid..) and useful substances (glucose, vitamins..). The filtered liquid that passes to Bowman’s capsule is similar to blood plasma but doesn’t contain proteins. 
  • Tubular reabsorption: as tiltered substances travel through the nephron’s tubule, they are reabsorbed, returning to the capillaries that surround them. In those substances nutrients are found (glucose, vitamins, amino acids…). as well as water and minerals that are needed to maintain the correct blood composition. Excretion molecules are not reabsorbed. Reabsorption of water is carried out in the loop of Hente


THE HEART 

Each half of the heart is subdivided into two chambers: an upper smaller chamber The heart is a hollow muscular organ. It is divided into two parts, the left and right, which are completely separate. named the atrium, and a larger lower chamber named the ventricle. In between the atrium and ventricle there is a valve named the atrioventricular valve. Its structure allows blood to pass from the atrium into the ventricle, but not the other way around. The valve located in between the right atrium and ventricle is named the tricuspid valve. The one on the left side is named the bicuspid or mitral valve. Several veins arrive at both atriums: two venae cavae to the right one andfour pulmonary veins to the left one. Two arteries originate from the ventricles: the pulmonary artery from the right one and aorta artery from the left one. At the start of those two arteries, there are valves named sigmoid valves, which are formed by three membranes that stop blood from coming back into the heart once it has been pumped out. The heart is formed by a thick wall of muscle tissue named myocardium. A double membrane named pericardium covers its exterior and its interior. It has a thin layer of cells named endocardium.