Exam 3 Study Guide: Biol 3350

Neuronal signaling

A type of communication in the body that uses neurons to transmit signals via neurotransmitters.

• fast

• addressed control

Hormonal signaling

A form of communication that involves hormones being released into the bloodstream to reach target organs.

• slow

• broadcasted signal

Pituitary gland

An endocrine gland that controls various hormonal functions in the body, often referred to as the 'master gland.'

HPA axis

Hypothalamic-pituitary-adrenal axis, a complex set of interactions involved in the stress response.

• engages sympathetic nervous system

• negative feedback

Insulin

A hormone produced by the pancreas that lowers blood glucose levels.

• uptakes glucose to be stored in the liver

Glucagon

A hormone produced by the pancreas that raises blood glucose levels.

• triggers glucose release from liver

HPG axis

Hypothalamic-pituitary-gonadal axis, which regulates reproduction and hormone production in the gonads.

Follicular phase

The first stage of the ovarian cycle, characterized by the maturation of the ovarian follicles.

Ovulation

LH triggers the release of an egg from a mature follicle in the ovary.

• egg to fallopian tubes to be fertilized

• 12-24 hours

Luteal phase

The last part of the ovarian cycle where the remaining oocyte develops into the corpus luteum.

Sertoli cells

Cells in the testes that provide support and nourishment to developing sperm cells.

• triggered by FSH

Leydig cells

Cells in the testes that produce testosterone.

• triggered by LH production

Iteroparous breeders

Species that reproduce multiple times over their lifespan.

Semelparous breeders

Species that reproduce only once in their lifetime.

Spontaneous ovulation

The natural occurrence of ovulation without external stimuli.

Induced ovulation

Ovulation that occurs as a result of mating.

Postpartum estrus

The period shortly after giving birth during which a female can conceive again.

• humans have prolactin to prevent this

Prolactin

A hormone critical for milk production in mammals.

Oxytocin

A hormone involved in milk ejection during breastfeeding.

Sequential hermaphroditism

A reproductive strategy where an organism can change its sex during its life.

Lower motor neurons

Neurons that directly control skeletal muscles.

Upper motor neurons

Neurons that convey impulses from the brain to lower motor neurons.

Stretch reflex

An involuntary response that occurs when a muscle is stretched.

1) input activates neurons

2) signal carried to spine

3) triggers interneurons to inhibit motor neurons for flexor muscles

4) movement of extensor muscles = movement

Flexion reflex

A withdrawal reflex that occurs when a painful stimulus is applied.

Muscle spindles

Sensory receptors located in the belly of muscles that detect changes in muscle length.

Central control

Regulation of rhythmic behaviors by the central nervous system.

Peripheral control

Regulation of rhythmic behaviors by peripheral mechanisms.

Concentric contractions

A type of muscle contraction where the muscle shortens while generating force.

Eccentric contractions

A type of muscle contraction where the muscle elongates while under tension.

Isometric contractions

Muscle contractions where the muscle length does not change.

Motor unit

A motor neuron and all the muscle fibers it innervates.

Twitch

A single contraction of a muscle fiber in response to a single stimulus.

Tetanus

A sustained muscle contraction resulting from rapid stimulation.

Summation

The process by which multiple stimuli combine to produce a more significant muscular contraction.

Smooth muscle

Type of muscle tissue that is involuntary and not striated, found in organ walls.

• not sarcomeres

• slower, longer contractions

• single nuclei

• single units connected with gap junctions

• multi-units controlled independently

Cardiac muscle

Involuntary striated muscle found only in the heart, characterized by intercalated discs.

Muscle fiber types

Classifications of muscle fibers based on their contraction speed and fatigue resistance.

Endurance exercise

Physical activity that enhances aerobic energy production.

• adding capillaries

• adding mitochondria

• adding heavy-chain myosin isoforms

Myostatin

A protein that inhibits muscle growth and regulates muscle mass.

PI3K-Akt1 pathway

A signaling pathway involved in cellular growth, proliferation, and survival.

• release IGF-1, bind to cell membrane

• PI3K + Atk1 protein activated

• synthesize to inhibit degradation

Satellite cells

Muscle stem cells that contribute to muscle repair and regeneration.

Muscle atrophy

The wasting or loss of muscle tissue.

• starvation, age, chronic illness

  • age = sarcopenia

Gas transport

The processes involving the movement of gases like oxygen and carbon dioxide in the body.

Simple diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Convection

The transfer of heat or gas through the movement of fluids with energy

• how air leaves lungs

Hematocrit

The proportion of blood volume occupied by red blood cells.

Oxygen equilibrium curve

A graphical representation of the relationship between oxygen saturation and partial pressure of oxygen.

Intracellular hemoglobin

Hemoglobin located within cells, primarily found in red blood cells.

Extracellular hemoglobin

Hemoglobin present in body fluids outside of cells.

CO2 transport

The process by which carbon dioxide is transported from tissues to the lungs for exhalation.