AP Biology Respiratory System

Regents Biology Why do we need a respiratory system?  For gas exchange  Need O 2 in  for cellular respiration  make ATP  Need CO 2 out  waste product O2O2 food ATP CO 2

Regents Biology Pathway of Air Mouth/nasal cavity - warm and filter the air Pharynx Larynx – voicebox Trachea (windpipe) - surrounded by rings of cartilage (protect and support) Bronchi (2) – lead to lungs Bronchioles – branches within lungs Alveoli – air sacs - Provide LOTS of surface area - Connect to circulatory system (capillaries) – functional unit of lungs

Regents Biology Moving gases into bloodstream  Inhale  O 2 passes from alveoli to blood  by diffusion  Exhale  CO 2 passes from blood to alveoli  by diffusion capillaries (circulatory system)

Regents Biology Gas exchange: Diffusion of gases  LOTS OF SURFACE AREA bloodlungs CO 2 O2O2 O2O2 bloodbody CO 2 O2O2 O2O2 capillaries in lungscapillaries in muscle In from outside To leave body supply excrete Pulmonary Circulation Systemic Circulation

Regents Biology Negative pressure breathing  Diaphragm – smooth muscle; moves down & expands chest cavity pulls air into lungs Inhale – air pulled in Exhale – air pushed out

Regents Biology Automatic Brain Control  You don’t have to think to breathe!  Primitive parts of brain coordinate breathing  Medulla (Nervous System)  measure blood pH   CO 2 =  pH (acid)  coordinate breathing, heart rate & body’s need for energy  Clothespin lab – remember?  Maintain homeostasis

Regents Biology Disorders  Bronchitis – inflammation of bronchi  Emphysema – alveoli break dec surf area – decreased lung capacity  Asthma – spasm of bronchioles  Pneumonia – fluid in lungs  Collapsed lung – no air in alveoli – usually some air left in alveoli to make breathing easier