Respiration Notes

RESPIRATION CONTENTS  Respiration  Breathing  Respiration in Plants  Respiration in Human  Mechanism of Respiration Figure : EPIBLEMA AND ROOT HAIR TAKE PART IN EXCHANGE OF GASES DIRECTLY IN YOUNG ROOTS RESPIRATION It is a biochemical process of enzyme including oxidative breakdown of organic compounds  By Leaves :  Leaves and Young Stems. Leaves and young inside living cells releasing energy in the form of stems are ideally suited to quick exchange of ATP. gases. The organs have a covering of nearly impermeable epidermis for reducing loss of water. BREATHING  The epidermis of leaves bears a number of The process of intaking O2 & releasing of CO2 aerating pores called stomata (singular stoma or known as breathing . stomata, Gk. stoma-mouth). Each aerating or stomatal pore is bordered a pair of guard cells. In RESPIRATION IN PLANTS most of the plants, the guard cells are kidney or  By young roots : bean shaped with inner walls being thicker and  less elastic than the outer walls. Air occurs in soil interspaces. Root hairs as well as epiblema cells of the young roots are in contact  When the stomata are open, gases diffuse into and with them. They are also permeable to metabolic out of the leaf as per their concentration gradient. gases. Oxygen of the soil air diffuses through root A gas which has come from outside first reaches hair-epiblema cells and reaches all internal cells substomatal chambers. From here, it diffuses to of the young root. Carbon dioxide produced by all the intercellular air spaces present in between root cells diffuses in the opposite direction. the mesophyll cells. If the stomata are open during night, oxygen from outside will diffuse into the leaves and young stems while carbon dioxide will diffuse out. It is due to respiratory  Trachea (Wind pipe) :  through the neck in front of oesophagus. It is gas exchange. supported by cartilage to prevent collapse. MAMMALIAN RESPIRATORY SYSTEM  The mammalian respiratory system consists of nasal cavity, pharynx, larynx, trachea, bronchi, It is long, tubular structure which runs downward  Primary bronchi :  These bronchioles and alveoli. are one pair of small thin walled tubular structure formed by the division of trachea. It further divides and end at alveoli.  Nostril :   It is also called external nares.   Nasal Chamber :   Lungs :  lungs are present in thoracic cavity on either side of heart. covered by pleural membrane. Nasal septum divides nasal cavity into two nasal chamber by the nasal septum. Epiglottis  Internal nares : Larynx  Trachea There are posterior opening of nasal chambers that leads into pharynx.  Pharynx :  Bronchus Pleural membranes Cut end of rib The pharynx provides passage to both air and food. Lung  Laryngopharynx :  Alveoli Pleural fluid Bronchiole Diaphragm It is the lower part of pharynx and has a slit like aperature called glottis, which can be closed by a Figure : HUMAN RESPIRATORY SYSTEM leaf like bilobed cartilage epiglottis, during swallowing of food bolus.  Larynx :   MECHANISM OF RESPIRATION It is also called voice box or adam's apple or Mechanism of breathing involves Two Phases. pomas adami. (A) Inspiration (B) Expiration  Vocal cord : In larynx, 2 pairs of vocal cord is found outer pair is false vocal cord whereas, inner pair is true vocal cord when air is forced through the larynx it cause vibration of true vocal cords and sound is produced.   Respiratory centre is in Medulla Oblongeta.  Inspiration :  Intercostal and phrenic muscles of diaphragm contract to increase thoracic cavity, therefore outside rushes inside.  Expiration :  Intercostal & phrenic relex muscles.  Due to decrease of thoracic cavity air pressure within lungs increase, the greater pressure within lungs force ful air from lungs to outside of body.  Gaseous Exchange :  Gaseous exchange occur in Alveoli following pressure gradient O2 from high pressure in alveoli diffuse into blood & CO2 from blood in alveoli.  Gaseous Transport :  O2 is carried by haemoglobin (in RBC). 100 ml of blood can carry ~20 ml of O2 max, CO2 is transported in form of bicarbonates in plasma.