Short notes on body fluids and cirulations of 1th biology
Answers
Answer:
This system is concerned with the circulation of body fluids to distribute various substances to various body parts. The circulatory system is also known as the cardiovascular system.
It is an organ system that allows blood to circulate and transport nutrients (such as electrolytes and amino acids), oxygen, carbon dioxide, hormones, and blood cells. These are circulated to and from cells in the body to nourish it. The components of the human circulatory system include the heart, blood, red and white blood cells, platelets, and the lymphatic system.
Functions of Circulatory System
(1) Transport of various substances such as nutrients, waste products, respiratory gases, metabolic intermediates (Such as lactic acid from muscle to liver), and vitamins hormones etc.
(2) Regulation of body pH by means of buffer, body temperature homeostasis, water balance etc.
(3) Prevention of disease by means of antibodies and antitoxins.
(4) Support or turgidity to certain organs like penis and nipples.
Differences between open and closed circulatory system
Open circulatory system
Closed circulatory system
(1) In open circulatory system blood flows through large open spaces and channels called lacunae and sinuses among the tissues.
(1) In closed circulatory system blood flows through a closed system of chambers called heart and blood vessels.
(2) Tissues are in direct contact with the blood.
(2) Blood does not come in direct contact with tissue.
(3) Blood flow is very slow and blood has very low pressure.
(3) Blood flow is quite rapid and blood has a high pressure.
(4) Exchange of gases and nutrients takes place directly between blood and tissues.
(4) Nutrients and gases pass through the capillary wall to the tissue fluid from where they are passed on to the tissues.
(5) Less efficient as volume of blood flowing through a tissue cannot be controlled as blood flows out in open space.
(5) More efficient as volume of blood can be regulated by the contraction and relaxation of the smooth muscles of the blood vessels.
(6) Open circulatory system is found in higher invertebrates like most arthropods such as prawn, insects, etc., and in some molluscs.
(6) closed circulatory system is found in echinoderms, some molluscs, annelids and all vertebrates.
(7) Respiratory pigment, if present, is dissolved in plasma; RBCs are not present.
(7) Respiratory pigment is present and may be dissolved in plasma but is usually held in RBCs.
Heart of vertebrates
Class of vertebrates
Characteristics
Example
(1) Pisces (= Branchial heart)
Thick, muscular, made of cardiac muscles, has two chambers (i) auricle and (ii) ventricle. The heart is called venous heart since it pumps deoxygenated blood to gills for oxygenation. This blood goes directly from gills to visceral organs (single circuit circulation). A sinus venosus and conus arteriosus is present. Lung fishes have 2 auricles and 1 ventricle.
Labeo
Scoliodon
Neoceratodus
(2) Amphibians
Heart consists of
(a) Two auricles
(b) Undivided ventricle
(c) Sinus venosus
(d) Truncus arteriosus
(conus + proximal part of aorta) Right auricle receives blood from all the visceral organs (deoxygenated) via precaval and post caval. Pulmonary artery carries deoxygenated blood to lungs for oxygenation. This blood returns to left auricle via pulmonary vein (Double circuit circulation)
Frog
Toad
(3) Reptiles
Heart consists of :
(a) Left and right auricle
(b) Incompletely divided ventricle
(Ventricle in crocodiles gavialis and alligator is completely divided)
(c) Sinus venosus
(d) Conus arteriosus divided into right systemic, left systemic and pulmonary arch.
Lizards
Snakes
Turtles
(4) Aves
Heart consists of
(a) Left and right auricle
(b) Left and right ventricle
(c) Complete separation of arterial and venous circulation
(d) Only right systemic arch is present
(e) Sinus venosus and truncus arterisious absent
Pigeon