apL1 - body systems, heart and circulation

• what are the 12 body systems?

  1. circulatory
  2. respiratory
  3. digestive
  4. urinary
  5. nervous
  6. endocrine
  7. reproductive
  8. skeletal
  9. muscular
  10. integument
  11. lymphatic
  12. cardiovascular
• what makes up the respiratory system?

  nasal passage

  trachea

  lungs
• what makes up the digestive system?

  stomach

  liver

  gall bladder

  large intestine

  small intestine
• what makes up the urinary system?

  kidneys

  urinary bladder
• what makes up the nervous system?

  brain

  spinal cord

  peripheral nerves
• what makes up the endocrine system?

  pituitary gland

  thyroid gland

  pancreas

  adrenal gland

  testes
• what makes up the skeletal system?

  cartilage

  bones

  joints
• what makes up the muscular system?

  skeletal muscles

  tendons
• what makes up the integument system?

  epidermis

  dermis

  hypodermis

  associated glands

  hair

  nails
• what makes up the lymphatic system?

  thymus

  lymph nodes

  lymphatic vessels
• what makes up the cardiovascular system?

  heart

  blood vessels
• what are the three body cavities?

  cranial cavity

  thoracic cavity

  abdominal cavity
• what makes up the thoracic cavity?

  right clavical

  cervical vertebrae

  sternocleido-mastoid muscle

  sternum

  intercostal muscles

  costal cartilages

  ribs

  diaphragm

  lumber vertebrae

  right lung

  larynx

  thyroid gland

  trachea

  left lung

  heart
• what makes up the abdominal cavity anterior part?

  diaphragm

  liver

  gall bladder

  omentum

  ascending colon

  caecum

  appendix

  stomach

  spleen

  transverse colon

  descending colon

  small intestines
• what makes up the abdominal cavity posterior part?


  oesophagus

  diaphragm

  inferior vena cava

  aorta

  right adrenal gland

  right kidney

  pancreas

  duodenum

  ascending colon

  caecum

  appendix

  rectum

  spleen

  splenic artery

  left kidney

  left ureter

  vertebral colon

  pelvic colon
• describe the structure of the heart.

  cone shaped

  hollow

  muscular organ

  10cm long (about the size of the owners fist)

  lies in the thoracic cavity a little more to the left than the right.
• describe the outer sac of the heart wall (pericardium).

  fibrous tissue

  continuous with tunica adventitia of great blood vessels

  fibrous nature prevents over distension of the heart
• describe the inner sac of the heart wall (pericardium).

  double layer of serous membrane

  outer layer termed parietal pericardium and lines the fibrous sac.

  inner layer termed visceral pericardium which is adherent to the myocardium.

  made up of flattened epithelial cells

  secretes serous fluid into the space between the parietal and visceral layers this allows smooth movements between them when the heart beats.
• describe the myocardium.

  specialized cardiac muscle only found in the heart

  microscopically it has "trellis" like appearance

  a sheet of muscle rather than many individual cells

  specialised structure allows for a wave of muscle contraction to spread over the whole sheet of muscular tissue.
• describe the endocardium.

  forms the lining to the myocardium

  thin, smooth glistening membrane

  continuous with tunica intima which lines the blood vessels

  consists of flattened epithelium cells
• explain the cardiac cycle.

  1. ventricles relax, atria contracts = atrial systole
  2. decreased vol + increased p in atria. p changes force blood into the ventricles through the AV. Vol and p in ventricles increase as blood falls in.
  3. ventricles contract, atria relax = ventricular systole decreased vol and increased p in ventricles. High p in ventricles opens the semi lunar valves. Blood forced out into the pulmonary artery and aorta.
  4. ventricles and atria relax = complete cardiac diastole. Higher p in pulmonary artery and aorta = semilunar valve close. Atria fills with blood due
• explain how the heart initiates a heartbeat.

  1. SAN (pacemaker) sets rythm by sending a wave of excitation over atrial walls. causing left + right atrium to contract at the same time.
  2. non-conducting collagen tissue delays wave of excitation to the ventricle allowing the atria to fully empty.
  3. AVN responsible for passing WoE onto the bundle of his, which conducts WoE to purkyne fibers.
  4. purkyne fibers carry WoE up ventricle walls causing them to contract simultaneously, from bottom up.
• describe the properties of capillaries.

  single layer of endothelial cells forming a tube

  fenestrations (gaps and branches)
• describe the properties of arteries.

  rigid, cylindrical shape

  thick walls

  no valves

  carry oxygenated blood

  small lumen to withstand high pressures
• describe the properties of veins.

  not rigid, slightly flattened

  thin walls

  valves to prevent back-flow of blood

  carry de-oxygenated blood

  large lumen
• what are the different types of arteries.

  arterioles = smallest

  muscular arteries = medium

  elastic arteries = largest
• what are the different types of veins.

  venules = smallest

  veins = largest
• what are the layers in arteries.

  tunica adventitia - containing fibroblasts

  tunica media - densely populated by smooth muscle cells

  basement membrane

  tunica intima - containing a thin layer of endothelial cells.

  layer of elastic tissue

  connective tissue
• what are the layers of the vein.

  tunica adventitia - containing fibroblasta

  tunica media - densely populated by smooth muscle cells

  basement membrane

  tunica intima - containing a thin layer of endothelial cells.

  very thin smooth endothelium

  less elastic fibers

  composed of collagenous connective tissue.
• what do we mean by blood pressure?

  the force of blood pushing against the walls of the arteries as the heart pumps out blood. BP maintained by cardiac output (amount of blood that leaves the heart) and vascular resistance ( resistance to the flow of blood through the blood vessels).
• why do we have blood pressure?

  circulation of blood around the body to supply enough oxygen.
• how do we measure blood pressure?

  BP = cardiac output x peripheral resistance

  cardiac output is the amount or volume of blood being pumped out by the left ventricles in a 1 minute period.

  cardiac output = heart rate x stroke volume

  e.g., 70 beats per min x 70 mls of blood = 4900 mls per min of cardiac output.
• what is normal blood pressure and what do the figures mean?

  Normal blood pressure: 120/80 mmHg Figures represent systolic (pressure when the heart beats) and diastolic (pressure when the heart rests) readings.
• how do we measure BP?

  every reading consists of 2 numbers.

  first number is the systolic blood pressure (highest level BP reaches when left ventricle contracts and pushes blood into the aorta.

  second number is the diastolic blood pressure (lowest level BP reaches as the heart relaxes between beats) (diastole).
• what influences our day to day blood pressure (hypertension - high blood pressure)?

  obesity

  smoking

  excess alcohol

  lack of exercise

  acute emotions (anger, anxiety)

  strenuous exercise (adrenalin, noradrenaline)
• what influences our day to day blood pressure (hypotension - low blood pressure)?

  low blood volume

  hormonal changes

  widening of blood vessels

  medicine side effects

  anaemia

  heart problems or endocrine problems

  shock