Exam 4 Physiology (Ch.11-14)

Hormone

Regulatory molecule secreted into the blood by the endocrine gland.

Endocrine Glands

Glands that secrete hormones directly into the bloodstream.

Exocrine Glands

Glands that secrete their products through ducts leading to the outside or a cavity within the body.

Pancreas

A unique gland that serves both endocrine (insulin and glucagon) and exocrine (digestive enzymes) functions.

Oxytocin Source

Hypothalamus.

Oxytocin Target

Uterus and mammary glands.

Effect of Oxytocin

Stimulates contractions of uterus and mammary glands.

ADH Source

Hypothalamus.

ADH Target

Kidneys.

Effect of ADH

Regulates water retention or elimination.

Commonalities of Regulatory Molecules

1. Target cells possess specific receptors. 2. Binding causes a change in target cell activity. 3. A mechanism must turn off the regulator's action.

Synergistic Hormone Interaction

Effect of epinephrine and norepinephrine on increasing heart rate.

Antagonistic Hormone Interaction

Opposing effects of insulin and glucagon regarding blood sugar regulation.

Mechanism of Action for Steroid Hormones

Hormone travels through the plasma membrane, binds to receptors in the cytoplasm, travels to the nucleus, binds to DNA, activating transcription and protein synthesis.

Phospholipase-C Second Messenger System Effect

Releases calcium ions from intracellular stores, activating various intracellular enzymes leading to physiological responses.

ACTH Target

Adrenal cortex.

Effect of ACTH

Stimulates secretion of cortisol/stress response.

TSH Target

Thyroid gland.

Effect of TSH

Stimulates secretion of T3 and T4 regulating metabolism.

GH Target

Most body tissues.

Effect of GH

Promotes growth of bone and muscles.

FSH Target

Gonadal tissues (ovaries and testis).

Effect of FSH

Promotes gamete production.

Prolactin Target

Mammary glands.

Effect of Prolactin

Stimulates lactation.

LH Target

Gonads.

Effect of LH

Stimulates ovulation/testosterone secretion.

Releasing and Inhibiting Hormones Source

Produced by specialized neurons in the hypothalamus.

Negative Feedback for Sex Steroids and Thyroid Hormone

1. Inhibits the pituitary's response to TRH. 2. Inhibits the secretion of TRH from the hypothalamus.

Cortisol Levels During Stress

Elevated due to CRH secretion from the hypothalamus.

Cause of Goiter

Iodine deficiency.

Organ Enlarged in Goiter

Thyroid gland.

Primary Cause of Cretinism

Lack of dietary iodine.

Effects of Cretinism

Stunted growth, intellectual disability, delayed motor development.

Grave's Disease

An autoimmune disease marked by thyroid enlargement and excessive hormone secretion.

Parathyroid Hormone Regulation

Regulation of calcium and phosphorus levels in the body.

Pineal Gland Secretion

Melatonin.

Functional Role of Melatonin

Regulates sleep and wake cycle/circadian rhythm.

Brain's Clock Mechanism

Pineal gland stimulated by the brainstem, regulated by hypothalamus receiving retinal input.

Origin in Muscle Physiology

Attachment of a muscle to an immovable bone.

Insertion in Muscle Physiology

Attachment to a movable bone.

Actions in Muscle Physiology

Movement caused when insertion is moved toward the origin.

Surface of Whole Muscle Covered

Connective tissue.

Bundle of Muscle Fibers

Fascicle.

Role of Actin

Makes up microfilaments, abundant in eukaryotic cells, allows unidirectional movement.

Role of Myosin

Converts chemical energy (ATP) to mechanical energy, generating force and movement.

Role of Titin

Holds M-Line and Z-disc in place; support protein.

Neuromuscular Junction Components

Point of connection between nerve and muscle fiber, includes presynaptic terminal, synaptic cleft, and postsynaptic membrane.

Motor Unit Components

Includes motor neuron, neuromuscular junction, and muscle fibers.

Mechanisms Contributing to Force of Contraction

1. Number of muscle cells in each motor unit. 2. Number of motor units activated at one time/recruitment.

Summation in Muscle Physiology

Combining multiple contractions to produce sustained muscle contraction.

Tetanus in Muscle Physiology

Continuous contraction of a muscle fiber stimulated repeatedly.

Muscle Fatigue

Loss of ability to maintain contraction.

Role of Creatine Phosphate

Provides energy for muscle contraction, rapidly generates ATP short term.

Preferred Energy Source at Rest

Fatty acids.

Energy Sources During Intense Work

1. Glycogen. 2. Fatty acids.

Role of Muscle Spindle Receptors

Detect changes in muscle length and rate of change; critical for regulating muscle tone.

Role of Golgi Tendon Organs

Monitor muscle tension.

Example of Reciprocal Innervation

Knee jerk reflex; hamstrings relaxed, quads contracted.

Hemiplegia Definition

Paralysis of one side of the body.

Paraplegia Definition

Paralysis of both lower limbs.

Quadriplegia Definition

Paralysis of all four limbs.

Primary Function of Blood

Transport cells, nutrients, gases, and dissolved matter.

Circulatory System Linked Systems

1. Digestive. 2. Respiratory. 3. Urinary. 4. Endocrine.

Hematocrit Definition

Ratio of volume of red blood cells to total blood volume.

Function of Albumin

Maintains osmotic pressure, prevents plasma leakage.

Function of Globulin

Produces antibodies for the immune system.

Function of Fibrinogen

Blood clotting.

General Function of Red Blood Cells

Transport oxygen from lungs to tissues and carbon dioxide back to lungs.

General Function of White Blood Cells

Protect the body against disease.

General Function of Platelets

Blood clotting.

Hematopoiesis Definition

Blood cell formation in red bone marrow.

Erythropoietin Function

Stimulates RBC production.

Agglutination Definition

Clumping of red blood cells.

Hemostasis Definition

Stoppage of bleeding; involves collagen exposure, vasoconstriction, platelet plug formation.

Cardiac Cycle Definition

Period from one ventricular contraction to the next.

Cardiac Cycle and Blood Pressure Relationship

Direct relationship; systole increases pressure, diastole decreases it.

Pacemaker Potential Definition

Slow spontaneous depolarization in the SA node.

Role of HCN Channels

Regulate heart rate and rhythm through spontaneous depolarization.

Conducting System of the Heart

Group of specialized cells initiating and propagating electrical impulses for heart contractions.

Functional Unit of Circulatory System

Capillary; site of nutrient, gas, and waste exchange.

Necessity of Venous Valves

Prevent backflow of blood in veins.

Atherosclerosis Definition

Clogging of arteries with cholesterol.

Atherosclerosis Impact on Heart Attacks and Strokes

Narrows/block arteries, reducing blood flow and oxygen supply.

Functions of the Lymphatic System

1. Transports interstitial fluid back to blood. 2. Transports absorbed fat. 3. Produces immune cells (lymphocytes).

Frank-Starling Law of the Heart

Greater blood fill during diastole increases force of contraction during systole.

Blood Distribution at Rest

Most found in veins and venules (about 60% of blood volume).

Edema Definition and Causes

Tissue swelling from fluid in intercellular spaces; can be caused by low plasma proteins, electrolyte retention, or increased capillary pressure.

Elephantiasis Definition

Condition caused by Filarial worms blocking lymphatic vessels.

Function of Angiotensin II

Constricts arterioles and increases blood pressure.

Blood Pressure Loss in Circulation

Occurs primarily across arterioles due to friction and resistance.

Myoglobin Definition

Protein that holds a reserve supply of oxygen in muscle cells.

Gaseous Neurotransmitter for Vasodilation

Nitric oxide (NO).

Bypass in Bypass Surgery

Creates a new route for blood flow, bypassing blocked coronary artery.

Peripheral Resistance Effect on Blood Pressure

Increased resistance raises pressure; decreased resistance lowers pressure.

Baroreceptors Regulation

Regulate both increases and decreases in blood pressure.

Korotkoff Sounds

Sounds heard while taking blood pressure.

Sound for Systole

Lub.

Sound for Diastole

Dub.

Dangers of Hypertension

Increased strain on heart, potential heart failure, arrhythmias, strokes.