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Excretory System. The Kidneys. regulate the volume and chemical make-up of the blood metabolize vitamin D . Kidney Structure. Pelvis: expansion of upper ureter (lies within kidney) Calyces: divisions of the renal pelvis Cortex: Outer Layer Medulla: Inner Portion

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The kidneys
The Kidneys

  • regulate the volume and chemical make-up of the blood metabolize vitamin D

Kidney structure
Kidney Structure

  • Pelvis: expansion of upper ureter(lies within kidney)

    • Calyces: divisions of the renal pelvis

  • Cortex: Outer Layer

  • Medulla: Inner Portion

    • Pyramids: triangular divisions of the medulla

  • Nephron the structural unit of the kidney
    Nephron: the structural unit of the kidney

    • Bowman’s Capsule: cup-shaped top of nephron

    • Glomerulus: network of capillaries surrounded by Bowman’s capsule

    • Renal Tubule:

      • Proximal Convoluted Tubule

        • Loop of Henle: extension of proximal tubule

      • Collecting Tubule

      • Distal Convoluted Tubule:

    Nephron structure
    Nephron Structure

    Filtration in the glomerulus
    Filtration: in the glomerulus

    • Blood flows into kidneys and more specifically into the glomerulus

    • The blood exerts pressure high enough to push water and dissolved substances out of the glomerulus and into the Bowman’s Capsule.

    Tubular reabsorption in the loop of henle
    Tubular Reabsorption: in the Loop of Henle

    • Substances move out of the renal tubules into the capillaries

    • Those substances reabsorbed include:

      • Water

      • Glucose

      • Sodium

    • Ureters: slender tubes that convey urine from the kidneys to the bladder

    • Bladder: collapsible muscular sac that, in males, is just anterior to the rectum, and in females, is anterior to the vagina and uterus.

    • Urethra: is a thin-walled muscular tube that drains urine from the bladder and conveys it out of the body.

    Mechanisms for urine volume control
    Mechanisms for Urine Volume Control

    • Adrenal Cortex: produces aldosternone

      • Stimulates tubules to absorb salt at a faster rate

      • Increases tubular reabsporption rates

  • Posterior Pituitary Gland: produces antidiuretic hormone (ADH)

    • Makes distal and collecting tubules permeable to water

    • Decrease amount of urine excreted

  • Micturition he act of emptying the bladder
    Micturition:he act of emptying the bladder

    • As urine accumulates, the bladder stretches and stretch receptors are activated.

    • Occurs when about 200 mL of urine has accumulated

    • impulses are sent to the brain and one begins to feel the urge to urinate

    • Activation of the micturition center in the pons signals the need to urinate

    Characteristics of urine
    Characteristics of Urine

    • clear and pale to deep yellow

    • slightly acidic

    • around 6. 95% of urine volume is water

    • largest solute component is urea, a product of protein breakdown

    • other nitrogenous wastes include creatine and uric acid

    • In certain diseases, urine composition will change dramatically.

    Abnormal urinary constituents can include
    Abnormal urinary constituents can include:

    • Glucose - due to diabetes mellitus

    • Proteins - due to hypertension or glomerulunephritis

    • Ketone bodies - due to starvation or diabetes mellitus

    • Leukocytes - due to urinary tract infection

    • Erythrocytes - due to a bleeding urinary tract.

    Thursday march 17

    Thursday March 17

    Excretory Exam