Exam 3 focus Phsio. Ch 15-16, 9

how is accommodation accomplished in the eye

The cilliary muscles move the ligaments holding the lens

which lens fixes hyperopia

convex

hyperopia

farsightedness

which lens fixes myopia

concave

myopia

nearsightedness

presbyopia

inability for the eye to see objects closer as you age

What are second messengers?

Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules (first messengers). They help amplify and propagate the signal within the cell.

What is the role of cGMP as a second messenger in vision?

cGMP is involved in the phototransduction pathway; it causes depolarization of photoreceptor cells in response to light, allowing the conversion of light signals into electrical signals.

How does cGMP affect photoreceptor cells when light is absorbed?

When light is absorbed, cGMP levels decrease, leading to hyperpolarization of the photoreceptor cells, which reduces the release of neurotransmitters and signals the presence of light.

What enzyme breaks down cGMP in photoreceptors?

Phosphodiesterase (PDE) breaks down cGMP, leading to a decrease in its concentration and causing hyperpolarization of the cell.

What is phototransduction?

Phototransduction is the process by which photoreceptors convert light into electrical signals, involving the activation of second messengers like cGMP.

What happens to cGMP levels in the dark?

In the dark, cGMP levels are high, keeping ion channels open and allowing depolarization of the photoreceptor cells, resulting in continuous neurotransmitter release.

What is the significance of the decrease in cGMP during light exposure?

The decrease in cGMP during light exposure leads to hyperpolarization of photoreceptor cells, which is essential for transmitting visual information to the brain.

Glycosomes

Glycosomes are where muscles store glycogen.

Myoglobin

Myoglobin is a protein that contains iron.

Sliding filament model

The actin and myosin must slide together to be able to lock together to make a muscle contraction by shortening the sarcomere.

Calcium ion

The ion responsible for myosin being able to bind to actin.

Mitochondria

The organelle that contains the highest concentration of calcium ions.

ATP

The energy source required for muscle contraction.

Neuromuscular junction

The site where calcium binds to the presynaptic neuron, triggering the release of ACH.

End plate potential (EPP)

The energy change that occurs around each side of the neuron, triggering Na+ and K+ channels.

Action potential

A rapid change in membrane potential that propagates along neurons and muscle cells.

Excitation-contraction coupling

The sequence of events by which an action potential in the sarcolemma causes myofilaments to slide and muscles to contract.

T-tubules

Structures involved in the transmission of the action potential into the muscle fiber.

Sarcoplasmic reticulum

The organelle that releases calcium ions during muscle contraction.

Motor unit

A single motor neuron and all the muscle fibers it innervates.

Latent period

The time between a stimulus and the start of muscle contraction.

Contraction phase

The phase when the muscle shortens and increases tension.

Relaxation phase

The phase when the muscle returns to its resting state.

Temporal or wave summation

Increased contraction force caused by repeated stimuli.

Recruitment

The addition of multiple muscle fibers to increase contraction force.

Isotonic contraction

When the muscle exerts enough force to move an item.

Isometric contraction

When the muscle exerts force without moving the item.

ATP requirements in muscle cells

Muscle cells need ATP for energizing myosin, breaking cross bridges, and moving calcium out of the SR.

Energy pathways in muscle cells

Glycolysis produces 32 ATP, anaerobic produces 2 ATP, and aerobic produces 2 ATP.

Muscle length and contractile force

The longer the muscle, the more force it can generate.

Factors contributing to contractile force

Amount of fibers and whether the muscle is fast or slow oxidative.

fast glycolytic fibers

are fast and use low oxygen.

Slow oxidative fibers

are slow and use lots of oxygen

fast oxidative fibers

are fast and use lots of oxygen

Is oxytocin a peptide

yes

Is ADH a peptide

yes

Is GH a peptide

Yes

Is TSH a peptide

yes

Is ACTH a peptide

yes

is FSH a peptide

yes

is LH  a peptide

yes

is PRL  a peptide

Yes

is PIH a peptide

yes

is GHRH a peptide

yes

is GHIH a peptide

Yes

is GnRH a peptide

yes

is CRA  a peptide

yes

is Aldosterone  a peptide

no

is cortisol  a peptide

no

is estrogen and testosterone a peptide

no

is glucoagon a peptide

yes

is insulin a peptide

yes

is CRA tropic

yes

is GnRH tropic

yes

is LH tropic

yes

is FSH tropic

yes

Is ACTH tropic

yes

is TSH tropic

Yes

What produces oxytocin

P. Pituitary

What produces ADH

P. pituitary

What produces Gh

A. pituitary

What produces TSH

A. pituitary

What produces ACTH

A. pituitary

What produces FSH

A. pituitary

What produces LH

A. pituitary 

What produces PRL

A. pituitary

PIh

Prolactin inhibiting hormone (dopamine)

GHIH

growth hormone inhibiting hormone

GnRH

gonadotropin releasing hromoone

CRH

corticotropin relasing hormone

What produces mineral corticoids

zona glomerlulosa

What produces glucorticoids

zona fasiuclata

What produces gomatricoticoids

zona retiarius 

What produces glucagon

Pancreas?

What produces insulin

pancreas

Stimulants for oxytocin

cervix streach

Stimulants for ADH

low blood pressure

Stimulants for GH

GHRH, deep sleep

Stimulants for TSH

low T3 T4

Stimulants for ACTH

CRH, stress

Stimulants for FSH

GnRH

Stimulants for LH

GnRH

Stimulants for PRL

nipple succling

Stimulants for glucocritocids

ACTH

Stimulants for glucagon

decreased blood glucose

Stimulants for insulin

increase blood glucose

Inhibitors for ADH

alcohol, high h2o intake

Inhibitors for GH

GHIH

Inhibitors for TSH

high t3 t4, GHIH

Inhibitors for ACTh

high glutocoricids 

Inhibitors for FSH

high gonadotropin level

Inhibitors for LH

high gonadotropin level

Inhibitors for glucocorticoids

corstisol

Function of oxytocin

contracts cervix