Rat Anatomy

  1. Rat
    • Phylum Chordata
    • bilateral symmetry
    • divided longitudinally: head, trunk, tail
    • homotherms: org that maintains body temp at constant lvl above environment
    • Males = big visible scrotum
    • Females = many nipples
  2. Head
    where all major sense organs including brain, mouth, and associated structures are
  3. Trunk
    main body of animal that terminates in region of anus or cloaca (posterior opening in birds, reptiles, amphibians)
  4. Tail
    • propulsion (eg fish, whales, crocs)
    • balance
    • thermoregulation and display
  5. Phylum Chordata ( 4 characteristics)
    • 1) pharyngeal gill
    • 2) notocord
    • 3) single hollow, dorsal nerve cord
    • 4) post anal tail
  6. Lungs function to replace gills in higher vertebrates
    notocord absent in adults usually
  7. Vibrissae
    • longs hairs on snout
    • tactile in function
    • sensitive to touch
  8. 2 Notible External Features of Mammal's mouth
    • fleshy lips
    • cheeks => cheek pouches can carry food or nesting stuff
  9. Rat Incisor
    • hardened enamel only at front
    • soft dentine on backside that erodes--> self sharpening
  10. Rat Oral Cavity
    formed by the hard palate anteriorly and boneless soft palate posteriorly
  11. Rat Eyes
    • iris pink because albinos lack pigments that color eye
    • un-pigmented eye is pink b/c of presence and color of blood
  12. Rat Ear - Pinna
    flap surrounding canal
  13. Vertebrate/Rat - double tubular system
    • trunk region of vertebrates constructed like double tubular system
    • "inner" tube = digestive tract
    • "outer" tube is body wall of organism
  14. Rat Diaphragm
    • divides coelom into thoracic and abdominal cavities
    • contracts (- pressure/ exhale) and relaxes (+ pressure/ inhale)
  15. Thoracic Cavity
    • contains heart and lungs
    • protected by rib cage
  16. Abdominal Cavity
    contains most of digestive tract and excretory system
  17. Linea Alba
    • narrow line of white connective tissue (mid-ventral)
    • extends from sternum to pelvis
    • muscles attached help compress abdomen
  18. Salivary Glands
    • Parotids
    • Submaxillaries
  19. Submaxillaries
    • large
    • located medially on ventral surface
    • two covering trachea
  20. Parotids
    • not well defined
    • on side of submaxillaries
  21. Parotid Duct
    • moves salivary enzymes from parotid gland to mouth
    • extends from parotid gland into mouth, lying on top of jaw muscle
    • visble white duct
    • Watch out for white facial nerve doral of it -> will not lead to paratoid gland
  22. Parotid gland
    can be traced by finding white parotid duct
  23. Lymph Nodes
    • four small yellow-whitish spheres
    • located anterior to submaxillaries
    • filter lymph fluid
    • part of immune system
  24. Lacrymal Gland
    • tear glands
    • found on side of neck, anterior to parotids
    • large and darkened
    • connect to eye by lacrymal duct
  25. Lacrymal Duct
    connects Lacrymal gland to eye --> Tears
  26. Facial Nerve
    • visible white strand connected to facial muscles
    • resembles parotid duct but more dorsal
  27. Masseter
    Jaw muscle
  28. Diaphram
    • major muscle of respiration
    • flap of muscle
    • seperates thoracic and abdominal cavities
    • contracts (inhale)/ relaxes (exhale)
  29. Repiratory Pathway
    Air- > Larynx -> Trachea (from laryngopharynx)---splits into two---> Bronchi --divides--> Alveoli (tiny sacs)
  30. Falciform Ligament
    attaches part of liver and diaphragm to abdominal wall
  31. Thoracic Cavity Overview (where is everything?)
    • includes heart and lungs
    • right atrium = dark lobe extending out
    • thymus = pink mass of tissue anterior (above) heart
  32. Thymus
    • lumph organ that decreases in size with age
    • white/pinkish, fat-like mass anterior of heart
    • makes T-cells
  33. Larynx
    • where air enters
    • contains vocal cords
    • connects to trachea (anterior of it) from laryngopharynx
    • food prevented from entering by epiglottis
  34. Pharynx (3 parts)
    • part of throat that connects inner nose to throat
    • at back of mouth
    • Anterior to larynx (right above it)
    • 3 parts: oro/naso/laryngopharynx
  35. Oropharynx
    mouth section
  36. Nasopharynx
    nasal section
  37. Laryngopharynx
    • Throat section
    • where vocal cords are
    • substances passing thru go to either esophgagus or larynx
  38. Epiglottis
    prevents food from entering larynx
  39. Cartilaginous Rings
    present on walls of trachea -> prevents collapse
  40. Trachea
    • conducts air into lungs
    • pink, small, and sponge-like
    • ventral/ anterior to esophagus (in front of it)
  41. Thyroid Gland
    • important gland in endocrine system
    • surrounds cephalic end of trachea
  42. Pericardium
    think outer membrane that surrounds heart
  43. Atria
    will appear small and dark in their collapsed state
  44. Ventricles (right and left)
    make up most of heart mass
  45. Aorta
    • visible anterior to heart (on top part)
    • carotid arteries connected to it
    • pumps out oxygenated blood
  46. Carotids
    • smaller arteries branching off aorta
    • carries oxygenated blood
  47. Veins
    carry deoxygenated from liver and anterior/lateral regions of body to heart
  48. Arteries
    lead away from heart
  49. Blood Flow Pathway through Heart
    Veins (deoxy blood ) -> Heart ->Vena Cava -> Right Atrium -> Tricuspid (one wave valve) -> Right Ventricle -> Semilunar valve -> Pulmonary Arteries (deoxy blood) -> Lungs

    oxy blood (from Lungs) -> pulmonary veins -> Left Atrium -> biscuspid valve -> Left Ventricle ->Semilunar valve -> Aorta -> rest of Body
  50. Pulmonary artery
    carries deoxygenated blood from right ventricle to lungs
  51. Pulmonary vein
    carries deoxygenated blood from lung to left atrium
  52. Atrio-Ventricular Valves
    the tricuspid and bicuspid
  53. Sphygmomanometer
    measures blood pressure
  54. Blood Pressure
    • Normal = 120/80
    • external pressure greater/equal to internal pressure of brachial artery = no blood flow
    • measuring pressure of brachial artery!!
  55. Systolic Pressure
    • sound heard due to force generated by contraction of left ventricle
    • "Lub-Dub" heart as pressure on brachial artery is released and the walls expand letting blood flow
  56. Diastolic pressure
    • Force generated due to the elastic walls of the brachial arteries
    • when sound disappears b/c blood flow is flowing smoothly
  57. "Lub-Dub"
    • Lub = atrio-ventricular valves (bicuspid and tricuspid)
    • Dub = semi-lunar valves closing
  58. Lymph Vessels
    • pick up interstitial fluid
    • return fluid to circulatory system
  59. Spleen
    • big part of lymph system
    • located dorsal to stomach -> bright red (same color as liver)
    • blood filtered and acted upon by lymphocytes and phagocytes w/in spleen
    • storage and destruction of red blood cells
  60. Digestive System Pathway
    Mouth-> Pharynx (throat) -> Esophagus -> Stomach -> Small Intestines (Duodenum -> Jujunum -> ileum) -> Caecum -> Colon (large intestine) -> Rectum -> Anus
  61. Esophagus
    • move food in mouth to stomach
    • no role in digestion
    • collapsed when not in use
    • dorsal/posterior to trachea (right behind it)
  62. Mesenteries
    blood vessels pass to and from organs via mesenteries
  63. Stomach
    • Store food
    • secretes hydrochloric acid (HCl) -> optimal for enzymes
    • posterior end contains pyloric sphincter
  64. Pyloric Sphincter
    reulates emptying of acidic chyme from stomach to small intestine
  65. Chyme
    semifluid mass of partially digested food
  66. Small Intestine
    • three regions: deodenum, jujunum, ileum
    • secretes from liver and pancreas enter deodenum to aid in digestion
  67. Pancreas
    • irregular, pinkish/grayish gland on mesentery below stomach (looks like chewed up bubble gum)
    • near first loop of stomach
    • pancreatic juices contain digestive enzymes
    • ->digestive enzymes that break down proteins, carbs, fats
    • ->bicarbonate ions that neutralize acidic chyme
    • also for endocrine system: makes hormones insulin, glucagon, etc
  68. Large Intestine (Colon)
    • absorb water
    • materials not absorbed = feces
    • makes ONE single loop and ends in rectum -> anus
  69. Caecum
    • beginning of large intestine
    • has special bacteria for herbovores to break down complex carbs like cellulose
  70. Kidneys/ pathway
    on dorsal wall of abdominal cavity

    Blood -> Kidney-> Renal Artery -> Renal Vein

    some blood enter nephrons
  71. Nephron
    • funcitonal unit of kidney
    • forms urine, regulates ionic balance, etc
  72. Ureter
    • where urine exits in kidney
    • Tugging it will move both bladder and kidney
  73. Excretory System
    Urine -> ureter -> Urinary Bladder -> Urethra
  74. Kidney Cortex
    outer section containing larger number of renal corpuscles
  75. Kidney Medulla
    • inner part composed of collecting tubules
    • tubles empty into ureter
  76. Male vs Female Ejaculatory Duct
    • Males: urethra extends distally into penis -> common urogenital tract
    • Females: seperate
  77. Uterus
    • Y-shaped structure against dorsal wall of abdominal cavity
    • ovaries at end of each uterine horn -> highly vascularized with bumps
  78. Fallopian tube (oviduct)
    • coiled white structure immediately adjecent to ovaries
    • conducts egg from ovary to uterus
  79. Fertilization
    occurs in oviduct/ fallopian tubes
  80. Implantation
    occurs in uterus
  81. Testes
    located in scrotum - pocket of skin
  82. Seminiferous Tubules
    where sperm is produced
  83. Sperm Pathway in Males
    Seminiferous Tubules -> Epididymis (caput -> caudal) -> Vas Deferens -> Ejaculatory Duct -> Uretra -> Penis
  84. Xiphoid Process
    small cartilaginous piece in lower part of sternum
  85. Skeletal System
    Skull -> Cervical Vertebrae (neck) -> Thoracic Vertebrae (ribcage area)-> Lumbar Vertebrae (bottom rib to pelvis)-> illium (pelvis bone) -> Sacrum (pelvis to butt) -> caudal vertebrae (tail)
Card Set
Rat Anatomy
Rat Anatomy