AP2 Unit 2 Exam

endocrine and respiratory systems

events of respiration

1) pulmonary ventilation

2) external respiration

3) respiratory gas transport

4) internal respiration

pulmonary ventilation

BREATHING

inspiration: oxygen moves into lungs

expiration: carbon dioxide exits lungs

external respiration

gas exchange at lungs

• oxygen flows out of lungs down its gradient into blood

• carbon dioxide flows out of blood into lungs down its gradient

• gases move down their pressure gradient

respiratory gas transport

oxygen and carbon dioxide transported between lungs and body by blood

association of oxygen and hemoglobin

internal respiration

• exchange of gases between blood and body cells (tissues)

• an opposite reaction to what occurs in lungs

Nervous System

• rapid

• short lived

• very specific response (nerve impulses/muscle contraction; last only as long as change is present)

Endocrine System

• slow acting

• long-lived

• broader response (hormones/organs; active even after change is gone)

Function of Endocrine System

• coordinates and directs activity of body’s cells

• tends to control internal environment of body to maintain homeostasis and reproduction

Chemical Messengers of Endocrine System

• Hormones: long-distance chemical signals; travel in blood or lymph

• Autocrines: chemicals that exert effects on same cells that secrete them

• Paracrines: locally acting chemicals that affect cells other than those that secrete them

Hormones

• secreted into bloodstream or ISF

• regulate metabolic activity of other cells in body

• respond in a receptor-hormone specific manner

Amino acid-based hormones

• derived from amino acids (non steroidal hormones)

• 3 types: proteins, peptides, amines

• large charged (water-soluble; hydrophobic) compounds (don’t require transport proteins)

• cannot diffuse across cell membrane

Steroid Hormones

• derived from cholesterol

• 2 types: sex and stress

• fat soluble and non polar (since water insoluble, needs a transport protein to travel to target cells)

• can diffuse across cell membrane into target cells

Lipid-Soluble Hormones (steroid and thyroid hormones)

• can enter cell

• act on intracellular receptors that directly activate genes

• DIRECT GENE TRANSCRIPTION

Water-Soluble Hormones (all amino acid-based hormones except thyroid hormone)

• cannot enter cell

• act on plasma membrane receptors

• act via G protein second messengers

• SECOND MESSENGER SYSTEMS

Hormonal Stimuli

• hormones activate other endocrine glands to secrete hormones

• Ex:

• hypothalamic hormones

• anterior pituitary hormones

• hypothalamic-pituitary-target

Humoral Stimuli

• changes in blood levels of certain ions or nutrients stimulate hormone release

• Ex:

• parathyroid hormone (declining blood calcium concentration stimulates parathyroid glands to secrete PTH; PTH causes calcium concentrations to rise, and stimulus is removed)

Nervous Stimuli

• nerve fiber impulses stimulate hormone release

• most under control of sympathetic nervous system

• Ex:

• Adrenal Medulla (sympathetic nervous system fibers stimulate adrenal medulla to secrete epi and norepinephrine)

Negative Feedback

How blood hormone levels are maintained

Permissiveness

one hormone cannot exert its effects without another hormone being present

Synergism

more than one hormone produces same effects on target cell, causing amplification

Antagonism

one or more hormones oppose(s) action of another hormone

Up-regulation

target cells form more receptors in response to low hormone levels

Down-regulation

target cells lose receptors in response to high hormone levels

• desensitizes the target cells to prevent them from overreacting to persistently high levels of hormone

Infundibulum

stalk that connects pituitary gland to hypothalamus

Glandular

tissue of anterior pituitary

Nervous

tissue of posterior pituitary

Growth Hormone

ANTERIOR PITUITARY (second-messenger, regulated by hormonal stimuli)

Non-tropic

• targets: many tissues, especially: cartilage, bone, muscle, and fat

• chemistry: protein

• function: important metabolic hormone

• promotes mitosis and protein synthesis (cell growth and division)

• directs skeletal muscle and long bone growth (determines final body size)

• causes liver to produce IGF-1 and undergo glycogenolysis (increases blood glucose levels and diabetogenic effects)

• utilizes fat for ATP production; many tissues switch to fatty acids as the main energy source/spares glucose and proteins (lean body mass and maintains glucose levels)

Prolactin

ANTERIOR PITUITARY (second-messenger, regulated by hormonal stimuli)

Non-tropic

• targets: mammary glands, reproductive organs

• chemistry: protein

• function: stimulates milk production in mammals; maintains milk production after childbirth

• stops ovulation temporarily following childbirth

• also plays roles in metabolism, immune system regulation, and reproductive health

Thyroid Hormone

THYROID

• targets: all cells

• chemistry: amine (derived from 2 molecules of tyrosine joined together)

• function: major metabolic hormone (regulates metabolism of all cells)

• controls energy production and metabolism (sets BMR)

• regulates vital body functions (HR and CO, body heat, weight, muscle/strenght, NS function, etc.)

• mobilizes glucose for usage (enhances effects of epi and NE)

Hypothyroidism

• underproduction of TH

• cretinism: low during childhood

• myxedema: low during adulthood

Hyperthyroidism

• overproduction of TH

• Grave’s Disease: toxic goiter and or exophthalmos

Thyroid-Stimulating Hormone (TSH)

ANTERIOR PITUITARY (second-messenger, regulated by hormonal stimuli)

tropic

• target: thyroid gland

• chemistry: amino acid based

• function: stimulates synthesis and release of TH

Adrenocorticotropic Hormone (ACTH)

ANTERIOR PITUITARY (second-messenger, regulated by hormonal stimuli)

tropic

• target: adrenal cortex

• chemistry: amino acid based

• function: stimulates adrenal cortex hormone production (cortisol and androgens mainly)

Gonadotropin Hormone (LH & FSH)

ANTERIOR PITUITARY (second-messenger, regulated by hormonal stimuli)

tropic

• target: ovaries and testes

• chemistry: amino acid based

• function: triggers ovulation, in males supports sperm production

Aldosterone

ADRENAL CORTEX (glomerulosa)

• nontropic

• mineralocorticoids

• direct gene transcription

• hormonal and humoral

• most tissues

• increases sodium reabsorption and potassium secretion

Cortisol

ADRENAL CORTEX (fasciculata)

• nontropic

• glucocorticoids

• direct gene transcription

• neural and hormonal

• most tissues

• increases blood glucose levels; promotes protein breakdown

Androgens

ADRENAL CORTEX (reticularis)

• nontropic

• sex hormones

• direct gene activation

• hormonal stimuli

• target peripheral tissues

• pubic and axillary hair development

Estrogen and Testosterone

• gonadal sex hormones

• steroids

• direct gene transcription

• hormonal stimuli

3 Main Stages of Stress Response

1) alarm reaction: initial response to stress

• body mobilized to prepare for physical activity

• catecholamines produced

2) stage of resistance: duration after initial stress

• body copes with stressors

• corticosteroids

3) stage of exhaustion: duration after chronic stress

• body’s reserves are depleted

• body fatigues and sickness ensues

Hypersecretion of GnH

• cause exaggerated male characteristics

• Hirsutism: male hair growth patterns in women

Hyposecretion of GnH

• results in fertility issues

• in severe cases, individuals may not sexually develop

Follicle Stimulating Hormone (FSH)

• aids in gamete production

Luteinizing Hormone (luteinizing hormone)

• aids in production of sex hormones

Addison’s Disease

• adrenal insufficiency

• due to insufficient hormone production of cortisol by adrenals

• caused by hyposecretion of ACTH by pituitary

• autoimmune disease of cortex

• infection or cancer

• abrupt stoppage of using steroids

Cushing Syndrome

• caused by hypersecretion of ACTH by pituitary which leads to elevated cortisol levels

• caused ACTH-secreting tumors

• hyperactivity of cortex

• exogenous steroids

Mineralocorticoids

regulate sodium and potassium levels in ECF to control blood volume and blood pressure

(aldosterone = “salty”)

Glucocorticoids

regulate blood glucose levels, suppress immune system and inflammation

(cortisol = “sweet”)

Androgens

produce androgens that are crucial for onset of puberty

(dehydroepiandrosterone [DHEA] = “sexy”, weak male hormone that can be converted into testosterone or estrogen)

Medulla

adrenal glands; inner neural tissue region (sympathetic NS)

Cortex

adrenal glands; outer glandular tissue region with 3 layers (endocrine sys)

Antidiuretic Hormone (ADH)

POSTERIOR PITUITARY

Neural Stimuli

• aids in water retention

• constricts arterioles

• target: collecting tubules of kidneys

• chemistry: peptide

• trigger: high plasma, osmolarity

Oxytocin

POSTERIOR PITUITARY

Neural Stimuli

• causes uterine contraction during: labor, sexual relations, breast feeding

• causes milk ejection during suckling

Glucagon

• produced by alpha cells of pancreatic islets

• increases blood glucose concentrations/secreted in response to a fall in blood glucose

Insulin

• produced by beta cells of pancreatic islets

• lowers blood glucose concentrations/secreted in response to a rise in blood sugar

Type 1 Diabetes

beta cells absent or do not make insulin

Type 2 Diabetes

beta cells make insulin but cells are non-responsive to insulin

referred to as adult onset

Atmospheric Pressure

pressure exerted by air surrounding the body

Intrapulmonary Pressure

pressure in alveoli

Intrapleural Pressure

pressure in pleaural cavity

Transpulmonary Pressure

pressure difference between intrapulmonary and intrapleural pressures

Dalton’s Law of Partial Pressures

• total atmospheric pressure is the sum of the individual contributions of each gas in air (mostly nitrogen)

Henry’s Law

gases will dissolve in liquids

• in a proportion equal to their partial pressure and

• in relation to their solubility in the liquid