Signs of Respiratory Disease Flashcards
What does the respiratory system defend against?
Inhaled - e.g. dust
Infectious - e.eg bacteria, mycoplasma
Outline the respiratory system defence mechanisms…
Airway smooth muscle tone Mucous production a mucocillary clearance Coughing Resident cells Infiltration cells Mediators
How does airway smooth muscle tone act as a respiratory defence mechanism?
Bronchoconstriction or dilation
Mediated by neural mechanisms, hormones or mediators
Describe the neural control of smooth muscle tone in the respiratory system…
Parasympathetic
- ACh acts on M1 and M3 receptors to cause contraction
Adrenal medulla
- Epinephrine acts on B2 receptors to cause relaxation
Describe how drugs target neural control of smooth muscle tone in the respiratory system…
Bronchodilators
Antagonise ACh receptors
Beta 2 agonists
Describe the cough reflex…
- Irritant receptors in receptors in resp tract
- Signal via vagus nerve
- To cough centre in brainstem
- Efferent motor side: vagus, phrenic, intercostal, lumbar, trigeminal, facial, hypoglossal
- Cough
How is the cough reflex switched off?
Opiod recepto agonists
- Butorphenol
Describe the resident cells that act as respiratory defence mechanisms…
Alveolar macrophages - phagocytosis foreign particles
Mast cells - release mediators
Lymphocytes
Which immunoglobins acts as a respiratory defence mechanism? How?
IgA - Involved in upper airways - inhibits adherence of bacteria to epithelium and binds and neutralises foreign particles
IgG - Involved in lower airway - binds and neutralises foreign particles and activate complement cascase
What are the infiltrating cells that act as respiratory defence mechanisms?
Neutrophils Eosinophils Basophils Lymphocytes Monocytes Platelets
What are the roles of mediators as respiratory defence mechanisms?
Physiological role in host defence - Airway smooth muscle tone - Blood flow and vascular permeability - Cell accumulation and activation - Mucus production - Neural reflex mechanisms - Antibacterial activity In excess damage host tissue Affected by anti-inflammatory drugs
What are the clinical manifestations of respiratory disease?
Cough and bronchoconstriction Sneezing Tachypnoea and hyperpnoea Respiratory distress Nasal discharge, epistaxis, haemoptysis Cyanosis Abnormal respiratory noise (stertor/stridor)
What is a cough? Why is it useful?
Sudden noisy expulsion of air through the glottis to clear mucous and other material from the larger airways. It facilitates removal of noxious substances
What are the stimuli for coughing?
Bronchoconstriction Excessive mucous Inhaled particles Cold or hot air Intramural or extramural pressure Epithelial sloughing Epithelial permeability
How can the character of a cough give you an idea of where the disease is occurring?
Upper airway = harsh, loud, non-productive
Lower airway = soft muted, productive
Painful conditions = muted cough
Guideline - never 100%
How can you tell if a cough is productive in an animal?
Look to see if the animal is swallowing after coughing.
How does sneezing occur?
Superficial reflex that originated in mucous membranes of nasal cavity easily induced by chemical or mechanical stimuli and always involving the upper respiratory tract
What can sneezing be a sign of?
Nasal disorders or can be secondary to more distal disorders
What is hyperpnoea/
Increase rate and depth of breathing
What is the normal breathing rate for:
- Horse
- Cow, sheep, pigs
- Goats
- Neonates (foal/calf)
- Dog
- Cat
- Rabbit
- 8-20
- 10-30
- 25-35
- 20-40
- 10-30
- 24-42
- 30-60
What are the causes of tachypnoea and hyperpnoea?
Physiological
- Pain, exertion, heat, anxiety
Pathologcial
- Response to high CO2, low pH or O2
- Compensation for metabolic acidosis
- Damaged CNS
- Pain
What is dyspnoea?
Respiratory distress Clinical signs of laboured breathing - Abnormal rate, rhythm and character - Nostril flaring - Exaggerated abdominal effort, abduced elbows
What is dyspnoea and respiratory distress often accompanied by?
Extended head and neck
Mouth breathing
What are the causes of inspiratory distress?
- Extrathoracic non-fixed airway obstruction
e. g. upper airway obstruction including larygneal hemiplegia and soft palate disorders - Restrictive diseases
e. g. limit lung expansion (pleural disease)
