Students can go through AP Inter 2nd Year Zoology Notes Lesson 2(a) Body Fluids and Circulation will help students in revising the entire concepts quickly.
AP Inter 2nd Year Zoology Notes Lesson 2(a) Body Fluids and Circulation
→ The circulatory system is an organ system that passes nutrients, gases, hormones etc., to and from cells in the body to supply nutrients, fight against diseases, stabilize body temperature and pH and to maintain homeostasis.
→ The human cardiovascular system is described as a closed, two cycle system namely pulmonary and systemic circulation system.
→ In pulmonary circulation deoxygenated blood Is pumped away from the heart via pulmonary artery to the lungs and returned, Oxygenated blood to the heat via the pulmonary vein.
→ In systemic circulation oxygenated blood pumped away from the heart to the rest of the body and returns deoxygenated blood back to the heart.
→ Blood is the most commonly used circulatory fluid by most of the higher organisms, including the humans.
→ In addition to blood another fluid, lymph also helps in transport of certain substances.
→ Lymphatic system is an open circulatory system.
→ The thoracic duct of the lymphatic system is the largest lymphatic vessel.
→ Spleen is the largest lymphatic organ and it also acts as reservoir of RBC.
→ Spleen also acts as haemopoietic organ until the fifth month of the gestation.
→ Human heart has four chambers, with two smaller upper chambers called atria and two larger lower chambers called ventricles.
→ Atria are thin walled blood receiving chambers.
→ Ventricles are thick walled blood pumping chambers.
→ Sino atrial node (SAN) has the ability to generate other potential without any external stimuli, hence called pacemaker.
→ The cardiac cycle consists of three phases namely atrial systole, ventricular systole and cardiac diastole.
→ The human heart beats 72 times per minute normally. Hence the duration of a cardiac cycle is about 0.8 sec.
→ Each ventricle pumps out 5 litres of blood per minute.
→ Thyroxine, epinephrine and nor ephinephrine increases the heart rate and cardiac output.
→ The blood pressure at rest is 120 mm Hg (systolic)/ 80 mm Hg (diastolic).
→ High blood pressure leads to heart diseases and also affects vital organs such as the brain and kidneys.
→ Blood pressure 140/90 mm Hg is considered as hypertension.
→ The body fluids blood and lymph called circulatory fluids help in the transport of various substances among various body parts.
→ Blood and lymph together consistute the fluid tissues in the human body.
→ Heart is Mesodermal in origin situated in the mediastinum. It is of the size of a clenched fist.
→ Human heart is a hallow muscular, cone shaped and pulsating organ. [IPE]
→ Structure of the heart: [IPE]
- Pericardium
- Heart wall with 3 layer:
(a) Outer epicardium (b) Middle myocardium (c) Inner endocardium - External Structure of heart includes
(a) Two upper chambers called atria, (b) Two lower chambers called ventricles. - Internal structure includes (a) Atria (b)Ventricles (c) Nodal tissue (d) Aortic arches.
→ Working of heart:
- Generation & conduction of action potentials [IPE]
- Cardiac cycle
- Double circulation (pulmonary circulation and systemic circulation)
→ Erythropoiesis starts in red bone marrow. [NEET 2015]
→ Blood = Plasma + RBC + WBC + Platelets [NEET 2015]
→ Whale has two separate circulatory pathways. [NEET 2015]
→ In mammals, Hepatic Vein normally carries largest amount of urea. [NEET 2016]
→ Serum differs from blood in lacking clotting factors. [NEET 2016]
→ The hepatic portal vein drains blood to liver from stomach and intestine [NEET 2017]
→ Blood pressure in the mammalian aorta is maximum during systole of the left ventricle [NEET 2015]
→ Blood pressure in the pulmonary artery is more than that in the pulmonary vein. [NEET 2016]
→ The QRS complex in a standard ECG represents depolarisation of ventricles. [NEET 2020]
→ The enzyme Thrombin is responsible for the conversion of inacitve fibrinogens to fibrins.