Human Biology: Circulation and Blood

• The left ventricle pumps blood to the entire body.

Gas Exchange

• Hemoglobin carries oxygen and carbon dioxide in different, not fairly equal, amounts.
• Breathing rate is regulated by the medulla of the brain.
• The nose filters, warms, and moistens air.
• Gas exchange occurs in alveoli.
• When carbon dioxide builds up in the blood, the pH lowers.

Red Blood Cells

• Red blood cells live 120 days.
• Red blood cells are not leukocytes; leukocytes are white blood cells.
• Red blood cells lack a nucleus.
• Red blood cells are formed in the bone marrow.
• Red blood cells carry oxyhemoglobin.

Human Circulation

• Arteries have thick muscular walls.
• The sinoatrial (SA) node is the heart's pacemaker.
• Leukocytes fight disease.
• Hemoglobin carries oxygen.
• The aorta carries oxygenated blood away from the heart.

Blood Clotting

• Fibrinogen is involved in blood clotting.
• Erythrocytes (red blood cells) are not directly involved in blood clotting.
• Thromboplastin is involved in blood clotting.
• Calcium ions are needed for blood clotting.
• Thrombocytes (platelets) are essential for blood clotting.

Blood Flow

• The vena cava empties into the right atrium, not the right ventricle.
• The right atrium leads to the tricuspid valve.
• Blood flows from the aortic semilunar valve to the aorta.
• Blood flows from the lungs to the pulmonary vein.
• The pulmonary vein empties into the left atrium

Blood Flow Order

• The correct sequence is: Right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium.

Human Circulation (cont.)

• Blood in capillaries travels slowly, facilitating diffusion of nutrients and wastes.
• Normal blood pressure is typically higher in males than in females.
• The average heart rate and pulse is about 70 beats per minute.
• Heart rate normally changes in response to physical activity.
• Arteries have thicker walls than veins.

Carbon Dioxide Transport

• The largest amount of carbon dioxide is transported to the lungs in the plasma as the bicarbonate ion.

Blood

• White blood cells are formed in the bone marrow.
• Platelets are cell fragments, not complete cells.
• Arteries do not contain valves; veins do.
• The liquid component of blood is called plasma.
• Red blood cells have a lifespan of approximately 120 days.

Hormone Matching

• Thyroxin comes from the thyroid gland.
• Oxytocin is produced by the posterior pituitary gland.
• Insulin is produced by the pancreas.
• Thyroid-stimulating hormone comes from the anterior pituitary.
• Adrenaline is produced by the adrenal medulla.

Hormone Functions

• Glucagon raises blood sugar.
• Insulin lowers blood sugar.
• FSH (follicle-stimulating hormone) stimulates the ovaries.
• Progesterone stimulates the uterine lining.
• HGH (human growth hormone) stimulates growth of long bones.

Endocrine System

• Endocrine glands are ductless.
• Parathormone regulates calcium and phosphate levels, not the fight-or-flight response.
• Islet cells in the pancreas produce both glucagon and insulin.
• Ecdysone controls metamorphosis in some insects.
• Polypeptide hormones bind with a receptor and trigger a secondary messenger.

Anterior Pituitary Hormones

• Glucagon is not produced by the anterior pituitary

Antidiuretic Hormone (ADH)

• The primary target of antidiuretic hormone is the kidney, specifically the collecting tubule of the nephron.

Tropic Hormones

• Tropic hormones are released by the hypothalamus and stimulate other glands.

Kidney

• Filtration in the Bowman’s capsule is nonselective.
• Reabsorption is selective.

Urea

• Urea is produced in the liver and excreted mainly by the kidneys.

Human Circulatory System

• Leukocytes fight germs.

ADH Effect

• ADH most directly affects the collecting tubule of the nephron.

Nervous System

• The parasympathetic nervous system is not associated with fight-or-flight; that is the sympathetic nervous system.
• Dendrites are sensory
• Axons carry an impulse away from the cell body
• The central nervous system consists of the brain and spinal cord
• The interneuron is located in the spinal cord

Parasympathetic System Stimulation

• Stimulation of the parasympathetic system leads to an increase in digestion, among other effects.