biology notes

HEARTBEAT ➤ The alternating  relaxations and contractions make up the cardiac cycle and one   complete  cardiac cycle makes one heartbeat.and in other words, one complete pulsation  of the heart  is called heartbeat. It is the complete regular movement movement of our  heart as it passes  blood around your body. STEPS OF CARDIAC CYCLE ➤ C omplete cardiac cycle consist of the following steps .   CARDIAC DIASTOLE ➤ Atria and ventricles relax and blood is filled in atria. this period is called cardiac   diastole.  In short, it is the period of relaxation of heart muscles.In one complete heartbeat,   diastole  lasts about 0.4 seconds. ATRIAL SYSTOLE ➤ It is the last phase in diastole during which the ventricular filling is  competed.    Immediately  after their  filling, both atria contracts and pump blood towards ventricles.   This period in  cardiac cycle is called  atrial systole.In o...

what is guttation  

OSMOREGULATION   THERMOREGULATION

  HOMEOSTASIS

CELL DEFINE CELL  

  SPINAL CORD ★ THE SPINAL CORD IS IN FACT A TUBULAR BUNDLE OF NERVES.   STARTS FROM; ★ IT STARTS FROM BRAIN STEM AND EXTENDS TO LOWER BACK. SPINAL CORD IS THE    CONTINUATION OF MEDULLA OBLONGATA. MEDULLA OBLONGATA NARROWS DOWN    INTO AN OVAL SHAPED HOLLOW CYLINDER, THE SPINAL CORD, RUNNING THROUGH     THE VERTEBRAL COLUMN. CONSIST OF; ★ IT CONSIST OF A VERY LARGE NUMBER OF NEURONS. THE CELL-FIBRES AND BODIES     OF WHICH ARE ARRANGED IN A DEFINITE PATTERN. COVERED BY; ★ LIKE BRAIN, SPINAL CORD IS ALSO COVERED BY  MENINGES. THE VERTEBRAL    COLUMN SURROUNDS AND PROTECTS SPINAL CORD. SIZE OF SPINAL CORD; ★ SPINAL CORD IS ROUGHLY 40cm LONG AND ABOUT AS WIDE AS YOUR THUMB FOR    MOST OF ITS LENGTH. REGIONS OF SPINAL CORD; OUTER REGION; ★ THE OUTER REGION OF SPINAL CORD IS MADE OF WHITE MATTER . ★ CONTAINING MYELINATED AXONS. CENTRAL REGION; ★ THE CENTRAL REGION IS BUTTERFLY SHAPED THAT SURROUNDS THE CEN...

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