1) Blood Circulates Away from the Heart Via Arteries. This Blood Can Be Deoxygenated At

BIOL 255 SI, Molly

EXAM 4 REVIEW, 11/14/16

4A

1) Blood circulates away from the heart via arteries. This blood can be deoxygenated at times and also oxygen-rich at other times. The main point is that arteries carries blood away from the heart.

2) Blood circulates back to the heart via veins. This blood can be oxygen-rich at times and also deoxygenated at other times. The main point is that veins bring blood back to the heart.

3) Blood will clot when there is no anticoagulant present and this produces serum and the blood clot. The red blood cells form the clot by using the protein that was present in the plasma, so the serum has fewer proteins than plasma.

4) The extracellular fluids include blood plasma(which has more protein than lymph or interstitial fluids), which are fluids found between red blood cells, white blood cells, and platelets that are suspended in plasma. The protein in blood plasma helps pull fluids back into the blood.

5) In the production of formed elements of the blood, hematopoiesis is the formation of blood cells which takes place in the red bone marrow. Here red blood cell production is referred to as erythropoiesis. The presence of reticulocytes, which are immature red blood cells, indicates that erythropoiesis is taking place, while production of White Blood Cells is referred to as Leukopoiesis.

6) In a Red Blood Cell count there are 4-6million Red Blood Cells percubic millimetres, which is about the size of the head of a pin.The number of reticulocytes increase with rapid erythropoiesis, normally 1-2%.

7) Before birth, blood cell formation takes place in the fetal yolk sac, liver, and spleen. By the 7th month, red bone marrow is the primary hematopoietic area. The fetus has Hemoglobin F (HbF) in its RBC which has a higher affinity to oxygen than Adult hemoglobin (HbA). This allows oxygen transfer from maternal HbA to fetal HbF.

4B

8) The left coronary artery, which is located in the artioventricular groove or coronary sulcus, supplies oxygenated blood to the circumflex artery and the anterior interventricular artery, which is located in the interventricular groove or sulcus.

9) The right ventricle pumps blood to the pulmonary trunk and on to the lungs via pulmonary arteries, while the left ventricle, which has a much thicker myocardium because it pumps blood to the aorta, distributes blood to the coronary arteries and systemic circulation.

10) In the sequence of excitation, the sinoatrial (SA) node generates an impulse about 75 times a minute, which stimulate the atria to contact and the impulse is passed to the atrioventricular (AV) node. The AV node delays the impulse for approximately 0.1 second, then the impulse passes from the AV node to the ventricles via the atrioventricular(AV) bundle, often referred to as the Bundle of His.

11) An age related change that affects the heart issclerosis, which makes valves tougher and stiffer and also thickens the valve flaps. There is also a decline in cardiac reserve and fibrosis or scarring of the cardiac muscle, and finally atherosclerosis in which plaques build up within the coronary vessels.

12) The heart is derived from mesoderm.

4C

13) Fluids escaping the circulatory system are returned by the lymphatic vessels.

14) Large arteries like the aorta are elastic or conducting arteries. There is not a lot of vasoconstriction taking place. These are thin walled and have less smooth muscle in the tunica media layer. They allow low resistance conduction of blood and can withstand and diminish large blood pressure fluctuations.

15) Arterioles, which are smaller arteries, have less elastic fibers and are thinner and smoother muscle. Arterioles regulate blood flow into capillaries by vasoconstriction or vasodilation.

16) The functions of the capillaries are: exchange of oxygen and carbon dioxide by diffusion, delivery of nutrients and hormones, and removal of metabolic wastes.

4D

17) Lymphoid cells are mainly lymphocytes T cells and B cells that protect the body against antigens, which are anything the body perceives as foreign, such as bacteria and their toxins, viruses, and mismatched transfused RBC or other transplanted tissues, as well as cancer cells.

18) T cells orchestrate immune responses in which the T cell, that matures in the thymus, attacks and destroys foreign cells, while B cells produce plasma cells that secrete antibodies, which are proteins that bind antigens, tagging them for removal from the body. B cells mature in the bone marrow.

19) The functions of the lymph nodes are:filtration of macrophages (which destroy microorganisms and debris entering via the afferent lymphatic vessels) and immune system activation (which monitor for antigens and initiate their removal).

20) Lymph nodes have two distinct regions: the cortex, which is the outer region, and the medulla,which is the inner region. The cortex contains follicles with germinal centers where you find mitotic B cells and dendritic cells. Housed deep within the cortex are T cells in transit. These T cells circulate continuously surveying blood, lymph nodes, and the lymphatic stream.

21) The spleen, which is the largest lymphoid organ, functions are: site of lymphocyte proliferation, immune surveillance and response (white pulp area), cleansing of the blood, storage and break down of products of old RBC’s, storage ofiron for later use by bone marrow, site of fetal erythrocyte production (which normally ceases after birth), and storage of blood platelets (red pulp area).

22) Lymphatic organs arise from the mesoderm except the thymus, which is endodermal in origin.

Other than the spleen and the tonsils, lymphoid organs are poorly developed at birth.

4E

23) The respiratory zone is the site of gas exchange and consists of bronchioles, alveolar ducts, and alveoli. The conducting zone provides a pathway for air to reach the sites of gas exchange and include other respiratory structure such as the nose, nasal cavity, pharynx, and trachea, and also the respiratory muscles such as the diaphragm and other muscles allowing ventilation.

24) Functions of the nasal mucosa and conchae during inhalation are to filter, heat, and moisten, while during exhalation they reclaim heat and moisture to minimize heat and moisture loss.

25) The Nasopharynx lies posterior to the nasal cavity is strictly an air passageway and is lined with pseudostratified columnar epithelium. The pharyngotympanic (auditory/Eustachian) tube open into the lateral walls of the nasopharynx. While the oropharynx serves as a common passageway for food and air and its epithelial lining is composed of protective stratified squamous epithelium.

26) The laryngopharynx serves as a common passageway for food and air, and is continuous with the trachea. It has 3 functions: to provide a patent airway, provide a switching mechanism to route air and food into proper channels with the use of the epiglottis (which is elastic cartilage covering the laryngeal inlet during swallowing), and voice production.

27) Vocal ligaments attach the arytenoid cartilage to the thyroid cartilage, which are lined with mucosal folds called true vocal cords. The medial opening between them is the glottis and these vibrate to produce sound as air rushes up from the lungs. The false vocal cords, or vestibular fold, are the mucosal foldssuperior to the true vocal cords. The false vocal cords play no part in sound production, but close the glottis when swallowing or holding your breath.

28) Speech is produced with the intermittent release of expired air while opening and closing the glottis. Pitch is determined by the length and tension of the vocal cords, along with the bigger/smaller the thyroid cartilage the lower/higher the voice. Loudness depends upon the force of air rushing across the vocal cords. The pharynx resonates, amplifies, and enhances sound quality.

29) The bronchial tree is composed of the larynx, trachea, bronchi, and bronchioles. The right and left bronchi begin at the last tracheal cartilage, which is referred to as the carina. The bronchi subdivide into secondary bronchi, each supplying a lobe of the lungs, and then subdivide again to form tertiary bronchi.

30) Bronchioles consist of cuboidal epithelium with a complete layer of circular smooth muscle and lack cartilage support and mucus producing cells. The last segment of the bronchioles as they enter the respiratory zone are referred to as terminal bronchioles where they feed into the respiratory bronchioles defined by the present of alveoli.

31) The alveolar wall is a single layer of type I epithelial cells that permit gas exchange by simple diffusion and also secrete angiotensin converting enzyme that helps increase blood pressure when needed. Additionally, type II cells secrete surfactant which reduces surface tension on the alveoli and allow them to stay open and expanded.

32) Peripheral chemoreceptors at the carotid and aortic bodies detect the levels of oxygen and carbon dioxide to stimulate respiration via the medulla.

33) The medullary respiratory centers contain the Dorsal Respiratory Group(DRG), which is the pacesetting respiratory center. It excites the inspiratory muscles and sets the normal breathing rate (referred to as eupnea) and is dormant during expiration. Also located here is the Ventral Respiratory Group (VRG), which is the expiratory area involved in forced inspiration and expiration.

34) The pons respiratory centers influence and modify the activity of the medullary centers by smoothing the transitions between inspirations and expirations. The pneumotaxic area continuously inhibits inspiration centers. The apneustic area stimulates inspiration centers, as in the case of taking a long deep breath.