Ch. 6 part 7 Respiratory System

receptors can be

ion channles or g protein couple receptors

. G-Protein Coupled Receptors (GPCRs) can be

Stimulating

Inhibiting

. G-Protein Coupled Receptors (GPCRs) mechanism

G protein is attached to the receptor and activated once something attached to the receptors

-When receptor is activated → G protein exchanges GDP → GTP

G-Protein Activation Cycle Active vs Inactive Forms

GTP bound → ACTIVE

GDP bound → INACTIVE

G protein has what for inactivating the G protein

GTP-ase

Converts:

GTP → GDP

how many types of G prtiens

1000 types

Gs is the

stimualting type and stimualtes pathway

Gs stimulating mechanism

Gs → ↑ cAMP

cAMP → activates protein kinase

Leads to cellular response

Gs stimulating end result

Glycogenolysis occurs

In smooth muscle → relaxation (vasodilation)

Gi inhibiting what occurs

gives no cAMP- no activate of PKA— inhibited Response

Gq is the what type

activation type

Gq second messengers

Ca²⁺

IP₃

DAG

IP₃ (Inositol 1,4,5-triphosphate): CAUSES

Causes Ca²⁺ release

IP₃ receptors on smooth muscle causes

Ca²⁺ release → muscle contraction

DAG: causes

Ca2+ influx

Effect of Ca²⁺ causes

-contraction of smooth muscle

-Leads to vasoconstriction

-Not in skeletal muscle

Different receptor and second message can cause in G proteins can cause

different responses

G-Protein Coupled Receptors hromones

Catecholamines

Catecholamines act via what in G proteins

adrenergic receptors

Alpha 1 (α₁)

Causes vasoconstriction

Beta 1 (β₁)

In heart

Causes:

↑ heart rate

↑ force of contraction

Beta 2 (β₂)

In smooth muscle

Causes:

Relaxation

Vasodilation

Hormones Using G-Protein Coupled Receptors (GPCRs)

most peptide hormones:

PTH

FSH

LH

Glucagon

Catecholamines

Calcitonin

ADH

OT (Oxytocin)

Hormone not Using G-Protein Coupled Receptors (GPCRs)

insulin

cAMP Formation

ATP is hydrolyzed → cAMP

Done via enzyme adenylyl cyclase

Leads to response

cAMP breakdown

cAMP → 5'-AMP

Occurs after response → termination of response

Enzyme required for cAMP breakdown

Phosphodiesterase (PDE)

f Adenylyl Cyclase helps

Converts ATP → cAMP

-for cAMP formation

cGMP to GMP is done via

PDE

cGMP causes what

vasodilation

GMP means

termination of vasodilation

second messenger example

Catecholamines

ACTH

FSH

LH

Glucagon

PTH

TSH

Calcitonin

Pinal gland makes which hormone

melatonin

he hypothalamus releases both

releasing and inhibiting factors, which help control the pituitary gland.

smallest hormone is

is TRH (thyrotropin-releasing hormone),

the pituitary gland secretes six key hormones

growth hormone (GH), prolactin, gonadotropins (including FSH and LH), thyrotropin (TSH), and corticotropin (ACTH).

Melanotrophin influences

skin pigmentation, but it's not a hormone itself.

the parathyroid glands produce which hormone

PTH (parathyroid hormone).

pancreas makes which hormones

insulin, glucagon, and somatostatin.

the thyroid gland produces which hormones

T3, T4, calcitonin

calcitonin,

lowers calcium levels in the blood.

glucagon does what

increases blood sugar

thymus produces

thymosin, which is important for T-cell development

adrenal crotex makes

cortisol-stress response

aldosterone- help regulate Na and K+

adrenal Medulla makes

catecholamines for flight and flight

Another name for pituitary gland

hypophysis