MCB 246 Exam 3

What are the primary functions of the respiratory system?

1. external respiration- gas exchange between air and blood
2. pulmonary ventilation- move air into and out of the lungs
3. protect respiratory surfaces- dehydration, temperature change, and pathogens
4. produce sound
5. produce olfactory sensation

Where are vocal cords found?

larynx

What are vocal cords in charge of?

producing sound

What are vocal cords composed of?

elastic connective tissue which extend anterior and posterior between thyroid and arytenoid cartilage which are covered in mucous

How does sound production happen?

air passes through the glottis, vibrating vocal folds, and producing sound waves

How can a voice pitch change?

by changing the tension placed on vocal cords

What is pitch?

frequency of sound waves

Why do men have a lower pitch than women?

men have thicker and longer folds than women

Intrapleural pressure

pressure generated in the pleural cavity, lower than intrapulmonary pressure

Intrapulmonary pressure

pressure generated in the lungs

Alveolar volume

collective volume of the alveoli within the lungs, associated with intrapulmonary pressure

How does intrapulmonary pressure change during inspiration and expiration?

equal to atmospheric pressure at the end of both inspiration and expiration

Pleural cavity

separates the lungs from the walls of the thoracic cavity

Intrapleural pressure

pressure exerted within the pleural cavity

How is intrapleural pressure related to intrapulmonary pressure?

intrapleural pressure is less than intrapulmonary pressure so that the lungs are able to remain inflated; usually 4 mmHg less than intrapulmonary pressure

How is a pressure gradient created within the thoracic cavity?

caused by a volume change which creates a pressure gradient between atmosphere and thoracic cavity

How does inhalation happen?

An increase in the volume of thoracic cavity, but a decrease in intrapulmonary pressure results in air moving into the lungs

How does exhalation happen?

A decrease in the volume of thoracic cavity, but an increase in intrapulmonary pressure results in air moving out resulting in exhalation

List the steps of quiet inspiration along with associated partial pressures

1. Intrapulmonary pressure=atmospheric pressure (760 mmHg), intrapleural pressure=756 mmHg
2. Intrapulmonary pressure becomes less than atmospheric pressure and air flows in


1. intrapleural pressure decreases to 754 mmHg, pleural cavity volume increases
2. alveolar volume increases and intrapulmonary pressure decreases to 759 mmHg

List the steps for quiet expiration along with associated partial pressures

1. intrapulmonary pressure= atmospheric pressure
2. intrapulmonary pressure becomes great than atmospheric pressure, resulting in air flowing outwards

a. pleural cavity volume decreases and intrapleural pressure increases to 756 mmHg

b. alveolar volume decreases and intrapulmonary pressure increases to 761 mmHg

What is pulmonary ventilation?

breaking, moving air from a higher pressure to a lower pressure

eupnea

quiet breathing

forced breathing

vigorous breathing that accompanies hard exercise of hard exertion

What are the muscles involved in quiet breathing (eupnea)?

diaphragm and external intercostals

What muscles are involved in forced inspiration?

sternoclediomastoid, scalenes, pectoralis minor, serratus posterior superior, and erector spinae

What muscles are in forced expiration?

internal intercostal, abdominal muscles, transversus thoracics, and serrates posterior inferior

Whta structures are involved in the conduction zone?

nose, nasal cavity, pharynx, larynx, trachea, bronchus, bronchiole, and terminal bronchiole

What structures are involved in the respiratory zone?

respiratory bronchiole, alveolar duct, and alveoli

What is respiratory minute volume?

amount of air inhaled or exhaled in a mine; Vt x f

Alveolar ventilation (Va= f X \[Vt-Vd\])

amount of air that reaches the alveoli and is available for gas exhange

Tidal Volume

the amount of air taken into or expelled out of the lungs

Inspiratory Reserve Volume

amount of air taken into the lungs following forced inspiration or quiet inspiration

Expiratory Reserve Volume

the amount of air expelled from lungs during a forced expiration, measure of chest and lung capacity

Residual volume

the amount of air left in the lungs following a forced expiration

Inspiratory capacity

tidal volume + IRV

functional residual capacity

ERV+ residual volume; amount of air remaining in lungs following an exhalation at resting level

Vital capacity

TV+ ERV+ IRV; max amount of air that can be released after a max inhalation

Total lung capacity

TV+ERV+IRV+RV

What is the relative partial pressure difference between alveoli and pulmonary capillaries?

* oxygen diffuses from the alveoli to blood
* carbon dioxide diffuses from blood to alveoli
* PO2 in the alveoli> PO2 of pulmonary capillaries

What is the relative partial pressure difference between systemic capillaries?

* oxygen diffuses from the blood into systemic cells
* carbon dioxide diffuses from the systemic cells into the blood

What is cooperative binding?

each O2 that binds to hemoglobin makes it easier for the next oxygen to bind

What affects the O2-Hemoglobin saturation curve?

* pH
* temperature
* BPG

What are the functions of the digestive system?

* Acquisition of nutrients from the environment
* anabolism
* catabolism

What are the two essential ingredients needed for catabolism?

1. oxygen
2. organic molecules broken down by intracellular enzymes

Name the accessory digestive organs

1. salivary glands
2. teeth
3. tongue
4. liver
5. bile duct
6. gall bladder
7. pancreas

Name the parts of the GI tract

1. esophagus
2. stomach
3. large intestine
4. small intestine
5. rectum
6. anus

What is the main purpose of ingestion in the GI system?

materials (solid/liquid) enter the digestive tract via the mouth

What is the main purpose of motility in the GI stomach

Movement or mixing of materials through the GI tract via voluntary/involuntary muscle contraction

What is mechanical digestion?

physical breakdown of ingested materials, crushing and shearing, and makes materials easier to propel along the digestive tract

What is chemical digestion?

the enzymatic breakdown of food into small organic fragments for absorption by the digestive epithelium

What is the function of secretion in the digestive system?

release of water, acids, enzymes, buffers and salts, happens by the epithelium of digestive tract

What is the function of absorption in the GI system?

* Movement of organic substrates, electrolytes, vitamins and water
* happens avross digestive epithelium
* goes into interstitial fluid of digestive tract

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How does the endocrine system function?

Regulates a long-term and wide-spread process

What is the main goal of the endocrine system?

maintain homeostasis

What is autocrine communication?

source of chemical message is also itself, can happen through interstitial fluid or blood

What is direct communication?

* exchange of ions and molecules between adjacent cells across gap junctions
* ex: heart
* happens outside intracellular fluid

Paracrine communication

* use chemical signals to transfer info from cells to cell within a single tissue
* a cell targets a nearby cell
* medium can be interstitial fluid or blood
* most common form of communication
* example: interferon/T-cells

Endocrine communication

* release chemicals into the bloodstream
* alters metabolic activities of many tissues and organs simultaneously

Synaptic communication

specialized type of paracrine where signals is released at specialized structure (synapse)

Neuroendocrine communication

* communication is a more specialized form of endocrine communication
* can happen in the bloodstream
* mediated by neurons instead of NEUROTRANSMITTERS

What are the major endocrine glands?

pineal gland, pituitary gland, thyroid gland, and adrenal gland

What are organs with endocrine cells?

skin, thymus, heart, liver, stomach, pancreas, small intestine, adipose CT, kidney, and gonads

What are the two components needed for endocrine communication?

1. target cell- specific cells with receptors that are needed to bind and read hormonal messages
2. hormones- stimulate synthesis of enzymes or structural protein

Where does regulation of hormone activity happen?

1. at the source- mediated by endocrine reflexes
2. at the target- mediates by receptor regulation
3. transport between transport proteins

What is down regulation?

* form of target regulation
* presence of a hormone triggers a decrease in number of hormone receptors
* when levels of a hormone are high, cells become less sensitive

What is up-regulation?

* form of target regulation
* absence of a hormones triggers the increase in number of hormones receptors
* when levels of hormones are low, cells become more sensitive

What is hormonal stimulation?

* type of endocrine reflex- target source in regulation
* arrival or removal of specific hormones
* ex: growth
* ex: anterior pituitary gland releases thyroid- stimulating hormone which stimulates thyroid gland to release thyroid hormone

What is humoral stimulation?

* type of endocrine reflex- source regulation
* release of a hormone is response to changes in the level of nutrient or ion in the blood
* ex: EPO in kindeys
* ex:blood glucose levels

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What is nervous system stimulation?

* endocrine reflex
* release of a hormones in response to stimulation by the nervous system
* ex: epinephrine and norepinephrine

What is a simple endocrine reflex?

* involves only one hormone
* controls hormone secretion by the heart, pancreas, parathyroid, and digestive tract

What is a complex endocrine reflex?

* one or more intermediary steps
* two or more hormones
* the hypothalamus

How are most endocrine reflexes controlled?

negative feedback mechanisms

What are some components of water soluble hormones?

have a shorter half-life, freely travel in the bloodstream to bind to cell surface receptors, effects are immediate and short-lived

What are some components of lipid soluble hormones?

travel in the bloodstream and are bound to transport proteins, effects are more delayed and long term, have a longer half-life

Syngeristic effect on hormone?

hormones work together to produce a greater effect (example: estrogen and LH)

What is a permissive effect on a hormone?

first hormone allows for activation of a second hormones

ex: thyroid and epinephrine

What is an antagonistic effect on a hormone?

one hormone causes the opposite effect of another hormones

ex: insulin and glucagon

How is most of the endocrine gland activity mediated in the body?

communication between the hypothalamus and anterior pituitary

What is another name for the anterior lobe?

adenohypophysis

What is another name for the posterior lobe?

neurohypophysis

Explain the anatomy of the neurophysis?

* contains unmyelinated axons of hypothalamic neurins
* two populations of neurons responsible for producing hormones of posterior pituitary

What does the supraoptic nucelus produce?

antidieuretic hormone

What does the paraventricular nucelus produce?

oxytocin

How are hormones transported in the anterior pituitary?

through the portal vessels

* blood vessels link two capillary systems
* entire complex is a portal system

How are hormones transported int he posterior pituitary?

* communications happens through the hypothalmaic neurons

What are the two kinds of hypothalamic regulatory hormones in the anterior pituitary

releasing and inhibitory hormones

What is releasing hormones?

* hypothalmaic regulatory hormones
* stimulate synthesis and secretion of one or more hormones from the anterior lobe

What are inhibiting hormones?

* prevent synthesis and secretion of hormones from the anterior lobe

What are some examples of inhibiting hormones?

* prolactin release-inhibiting hormone
* somatostatin inhibits growth hormone-releasing hormone
* melanocyte-stimulating hormones releasing-hormone

tropin

hormones that induce the production of other hormes

tropic hormones

hormones whose targets are endocrine glands

trophic effects

growth promoting effects

What are some hormones of the anterior pituitary gland?

* thyrotropin-inducing releasing hormone
* prolactin-releasing hormones
* gonadotropin-releasing hormone
* corticotropin-releasing hormone
* growth-hormone releasing hormone

Explain hypothalmic-pituitary reflexes

anterior pituitary hormones are mediated by complex endocrine reflexes

TRH hormones pathway

TRH-thyroid stimulating hormone- thyroid gland- tyroid hormones

CRH hormone pathway

CRH-ACTH-adrenal cortex- glucocorticoids

GnRH hormone pathway

GnRH-FSH-Testes-Ovaries(inhibin/estrogen)

GnRH-LH- Ovaries(progestins/estrogens)- androgens

What is peristalsis?

alternating contraction sequence of inner and outer layer of smooth mucle, propels food from mouth to anus

What is segmentation?

backward and forward motion that lack directional movement, blends ingested materials with secretions

What does the enteric system control?

motility (myenteric plexus) and secretion (submucosa plexus)