Biology Chapter on Hormones and Memory

The phase following repolarization where the membrane potential becomes even more negative than the resting potential due to the continued efflux of potassium ions.

The phase following depolarization where the membrane potential briefly returns towards the resting potential, primarily due to the inactivation of sodium channels.

The difference between the resting membrane potential and the equilibrium potential for potassium is primarily due to the active pumping of sodium and potassium ions by the Na+-K+-ATPase pump, counteracting their passive movement.

The transverse tubule (T-tubule) is an invagination of the sarcolemma that allows action potentials to travel from the cell surface deep into the muscle fiber, ensuring uniform contraction.

Electrical synapses allow direct ion flow between neurons through gap junctions, enabling very rapid transmission of signals.

Calcium ions that bind to troponin, triggering muscle contraction, are released from the sarcoplasmic reticulum, a specialized organelle within muscle fibers.

The sarcomere is the basic unit of a muscle fiber, composed of overlapping actin and myosin filaments responsible for muscle contraction.

The terminal cisternae are enlarged regions of the sarcoplasmic reticulum that store and release calcium ions during muscle contraction.

The hippocampus does not store declarative memory. It plays a crucial role in converting short-term memories to long-term memories but doesn't actually hold the information itself. Think of the hippocampus as a bridge, not a storage room.

Long-term potentiation involves an increase in calcium levels within the post-synaptic terminal, not the pre-synaptic terminal. The calcium influx triggers a cascade of events that strengthen the synaptic connection between neurons.

Neurogenesis, the creation of new neurons, occurs in the olfactory bulb and hippocampus. These regions constantly generate new neurons throughout life.

Agnosia is a neurological condition where someone cannot recognize objects or stimuli despite having intact sensory systems. They may see an object but not be able to name it or understand its purpose.

Tongue apraxia is a motor control disorder affecting speech and not a manifestation of left parietal cortex damage. It involves difficulty planning and executing tongue movements needed for speech. Left parietal cortex damage is linked to other apraxias related to spatial awareness and body representation.

Sensitization involves an increased response to a repeated stimulus. It's the opposite of habituation where repeated stimuli causes a decreased response. Sensitization is often associated with fear or pain responses.

Declarative memory is the type of memory that requires conscious effort to retrieve. It includes facts, events, and personal experiences. Declarative memory relies on the hippocampus and other medial temporal lobe structures.

Explicit or declarative memory is a type of long-term memory and requires conscious effort to recall. It's not a type of implicit memory, which is learned unconsciously and doesn't require conscious recall. It's also dependent on the hippocampus and the medial temporal lobe.

The absence of anti-Mullerian hormone on the X chromosome causes the gonads to develop into ovaries.

The presence of testosterone causes the Wolffian duct to degenerate.

The menstrual cycle consists of four phases: Follicular Phase, Ovulation, Luteal Phase, and Menses.

Inhibin is a hormone produced by the ovaries and it does NOT regulate the uterine cycle.

Menses is the shedding phase of the uterine lining, not a continuous phase of the cycle.

If fertilization is successful, the shedding of the uterine endometrium is prevented.

The Total Body Water (TBW) of an adult is typically around 60% of their body weight.

The seminal vesicles secrete a milky, slightly acidic fluid containing citric acid, proteolytic enzymes, acid phosphatase, and seminal plasmin.

Carbohydrate moieties on the cell surface play crucial roles, including cell recognition, adhesion, and signaling. They form the glycocalyx, a protective layer that also contributes to cell-cell interactions. These moieties can also act as receptors for various molecules and influence immune responses.

Negative feedback is a vital regulatory mechanism used by the body to maintain homeostasis. It works by counteracting deviations from a set point, like a thermostat adjusting temperature. When a factor increases, negative feedback mechanisms lower it, and vice versa, thus restoring balance.

Duchenne Muscular Dystrophy (DMD) is a genetic disorder characterized by a lack of dystrophin protein. This protein is crucial for maintaining the structural integrity of muscle fibers. Without dystrophin, muscle degeneration occurs, leading to progressive muscle weakness and paralysis.

Phagocytosis is a process of cellular engulfment where a cell ingests and destroys foreign particles or cellular debris. It begins with receptor-ligand binding, followed by membrane invagination, vesicle formation, and ultimately the breakdown of the ingested material.

After the first meiotic division of spermatogenic cells, secondary spermatocytes are produced. These cells are haploid, containing half the number of chromosomes as the original spermatogonia.

The hydrostatic pressure exerted by blood in the glomerular capillaries forces fluid and small solutes out of the capillaries and into Bowman's capsule, initiating filtration.

The thick ascending limb is impermeable to water, but actively pumps sodium ions out, making the tubular fluid more dilute.

The collecting duct is impermeable to water unless ADH is present. ADH allows water to diffuse passively back into the blood, leading to concentrated urine.

The proximal tubule reabsorbs most of the filtered water, along with electrolytes and nutrients, regardless of hormone influences.

Renin is released in response to low renal blood pressure, triggering the renin-angiotensin-aldosterone system (RAAS) to raise blood pressure.

Furosemide directly inhibits the Na⁺-K⁺-2Cl⁻ symporter in the thick ascending limb, reducing sodium and water reabsorption, leading to increased urine output.

Glucose in the blood draws water into the tubular fluid through osmosis, leading to an increase in urine volume.

Compensatory mechanisms lead to an increase in afferent arteriole resistance to maintain glomerular filtration pressure and counteract the stenosis.

Aldosterone is a hormone produced by the adrenal cortex that plays a crucial role in regulating sodium reabsorption in the distal tubule and collecting duct of the nephron. It increases sodium reabsorption, leading to increased water retention and higher blood pressure.

A urinary tract obstruction, such as a kidney stone or enlarged prostate, can interrupt the flow of urine, causing pressure to build up in the kidneys. This pressure can reduce the glomerular filtration rate (GFR), the rate at which blood is filtered by the kidneys.

In the absence of ADH, the collecting duct becomes less permeable to water. This results in reduced water reabsorption, leading to increased urine production and potentially dehydration.

Sodium reabsorption in the thick ascending limb of the Loop of Henle is an active process. Sodium ions are actively transported out of the tubule lumen, along with potassium and chloride ions, contributing to the concentration gradient in the medulla.

Diabetes insipidus is a condition where the body doesn't produce enough antidiuretic hormone (ADH). This leads to impaired water reabsorption in the collecting duct, resulting in excessive urination and dehydration.

Glucose reabsorption in the nephron primarily occurs in the proximal tubule through sodium-glucose cotransporters. These transporters bind to both sodium and glucose, allowing them to be transported across the tubular membrane together.

Angiotensin II is a potent vasoconstrictor that increases blood pressure by constricting blood vessels. It also stimulates aldosterone release, leading to increased sodium reabsorption and further blood pressure elevation.

Atrial natriuretic peptide (ANP) is a hormone secreted by the heart in response to high blood pressure. It promotes sodium excretion, reduces blood volume, and lowers blood pressure.