EXAM 4

• The function of the circulatory system is to transport gases, products of digestion, hormones, waste products, heat, water and ions.
• The cardiovascular system consists of blood, blood vessels, heart, and lymphatic system.
• The lymphatic system consists of lymph, lymphatic vessels, lymphatic tissues, and Choi and Hong, 2012.
• Microcirculation regulates and supports cell metabolism by adjusting blood flow according to nervous, hormonal, and local activity.
• The heart is supplied and drained by coronary vessels, valves, and has a pacemaker (region of sinus venosus) or sino-atrial node.
• The heart consists of the atrium, ventricle, and conus arteriosus (bulbus cordis).
• Hagfish lack major nerves innervating the heart to stimulate contraction, also known as the Branchial Heart.
• Monotremes, or egg-laying mammals, are a type of mammal that do not produce pituitary hormones.
• Oxytocin, a hormone, has a target of the smooth muscle layer of the uterus, also known as the myometrium.
• Hormones such as vasopressin or antidiuretic hormone (ADH) promote water conservation within kidneys.
• Smooth muscle cells of the myometrium contract during labor and delivery.
• Cells within the neurohypophysis do not produce pituitary hormones.
• Cells of the mammary gland, known as contractile myoepithelial cells, are a type of smooth muscle cell.
• Axons of neurosecretory neurons of the hypothalamus project into the neurohypophysis, where their secretions are released into blood vessels or temporarily stored.
• Accessory hearts include the Cardinal, Caudal, and Portal (only in Hagfish).
• The circulatory system of hagfish lacks cardiac muscles, and atrial contraction assists ventricular filling.
• The circulatory system of hagfish is single atrium partially divided, with pulmonary veins either sinus venosus or directly to the left atrial chamber.
• The alignment of the interventricular septum, atrioventricular plug, and interatrial septum establishes internal channels within and through the heart.
• In lungfish, separate streams of blood returning from the systemic and pulmonary circuits differ in oxygen tension.
• In amphibians, underproduction of thyroid hormone arrests larval growth, affects the integument, and causes changes in reproduction.
• Thyroid hormones regulate metabolism, growth and metamorphosis, reproduction (gonadal maturation except amphibians), and are synthesized in all vertebrates.
• In endotherms, the thyroid gland is responsible for oxygen consumption and heat production in tissues.
• Parathyroid gland is absent in fish and neotenic salamanders, and is present in amphibians, reptiles, and birds, either on the thyroid or dispersed among major veins in the neck.
• Thyroid gland is a single- or double-lobed organ dispersed masses of follicles, and arises as an outgrowth of the floor of pharynx.
• In mammals, the parathyroid gland is usually embedded or near the thyroid gland.
• In reptiles, a temperature of 30 ° C causes underproduction of thyroid hormone.
• Underproduction of thyroid hormone results in stunted growth (cretinism), while overproduction causes hyperactivity, nervousness, bulging activities and rapid weight loss (Grave’s disease).
• Thymus gland is a composite organ that coordinates the response to stress, with adrenocortical tissue producing Corticosteroids.
• Thyroid gland produces, stores and releases hormones such as Thyroxine (Tetraiodothyronine) and Triiodothyronine.
• Parathyroid gland produces Parathormone, which regulates blood calcium levels.
• Lungless salamander is 90% cutaneous respiration, 10% buccal respiration, lacks a left atrium, and the compartment that would receive blood returning from the lungs is reduced or perforated.
• Lymphatic tissue is a collection of connective tissue & free cells (leucocytes, plasma cells, &macrophages), removes & destroys harmful foreign material, and plays a role in body defense & resistance to diseases.
• The peripheral nervous system consists of neurons carrying information to and from the central nervous system, nerves and ganglia, and consists of afferent neurons carrying sensory signals to the central nervous system and efferent neurons carrying signals to the periphery.
• The lymphatic system re-circulates fluid from tissues back to the cardiovascular system, drains excess fluid, supplies nutrition & O2, transports proteins, absorbs fats from intestine, and plays a role in body defense & resistance to diseases.
• Motor neurons carry signals to skeletal muscles, while autonomic nervous system (ANS) regulates smooth and cardiac muscles, with two divisions: the sympathetic nervous system and the parasympathetic nervous system.
• Lymphatic vessels are a blind-ended tubular system with no pump, one-way movement of lymph (skeletal & smooth muscles), and harmful materials enter.
• The nervous system has the ability to respond to stimuli, circuits of neurons propagate electrochemical signaling between cells, enhance survival and reproductive success, and consists of the brain and the spinal cord.
• Lymph nodes are a collection of lymphatic tissue (connective tissue & free cells), filter lymph before it returns to blood, and contain defense cells such as Lymphocytes and Macrophages.
• Chondricthees and primitive fishes lack a true lymphatic system (hemolymphatic system), while amphibians, reptiles, birds, and mammals have a lymphatic system.
• Lymph consists of water, proteins, ions, glucose, fats, white blood cells (Lymphocytes), and is part of the immune system.