anatomy final exam review

Central nervous system

• brain

• spinal cord

Peripheral nervous system

nerves that link CNS with rest of body

neurons

conduct nerve impulses

neuroglia

protect and support neurons

basic parts of a neuron

• dendrite

• cell body

• axon

schwann cell

type of glial cell in the peripheral nervous system that forms the myelin sheath around neuronal axons.

oligodendrocyte

type of glial cell in the central nervous system that produces myelin to insulate neuronal axons.

depolarization and repolarization

1. Depolarization - stimulus causes sodium channels to open, allowing sodium to flow into the cell

2. Beginning of repolarization - potassium channels open allowing potassium to flow out of the cell

3. Repolarization- sufficient outflow of potassium has restored negative internal charge and positive external

refractory period

neuron is insensitive to additional stimulus

Absolute refractory period

period during which a neuron cannot fire another action potential, regardless of stimulus strength.

relative refractory period

period during which a neuron can fire another action potential but only with a stronger-than-normal stimulus.

threshold stimulus

• change in membrane potential required to cause adjacent membrane to depolarize

• starting the conduction of a nerve impulse

• All or nothing principle

• minimum level of stimulation needed to trigger an action potential.

saltatory conduction

• transmission of the impulse occurs gap to gap (nodes of Ranvier)

• allows increased speed of nerve transmission

Acetylcholine

• very common NT in body

• can be excitatory or inhibitory depending on location

• excitatory at the somatic neuromuscular junction

• inhibitory on the heart rate (slows)

excitatory Neurotransmitter

• depolarize neuron

inhibitory neurotransmitter

• hyperpolarize a neuron, less likely to fire reduces likelihood of action potentials

norepinephrine

fight or flight

epinephrine

also “fight or light” but can be released from the adrenal medulla as a hormone as well as NT

dopamine

Found in brain and is important for autonomic functions and muscular controol

GABA and Glycine

• inhibitory NT

• GABA in brain

• Glycine in spinal cord

• Some tranquillizers affect GABA receptors to increase their inhibitory activity in the brain

• valium- diazepam

cerebellum

allows coordinated movement, balance, posture and complex reflexes

cerebrum

higher-order functions

conscious movement

thalamus

• relay center for sensation and motor impulses

• interprets sensation before sending to cerebrum

• emotions, language and memory

hypothalamus

regulates internal environment, including temperature, hunger, thirst, and circadian rhythms.

brainstem

• subconscious basic life support functions

• Cardiac, resp, vasomotor centers

cerebrospinal fluid

• fluid that bathes and protects the brain and spinal cord

blood-brain barrier

• a functional barrier separating the capillaries in the brain from the nervous tissue itself

• walls are relatively impermeable

• barrier prevents many drugs, proteins, ions and other molecules from passing into the brain

spinal dorsal root

carries sensory info from body to spinal cord

spinal ventral root

carries motor info from spinal cord to body

clinical signs of sympathetic stimulation

• bronchodilation

• increased HR and contractability

• vasodilation to muscles

• vasoconstriction to GIT

• pupil dilation

clinical signs of parasympathetic stimulation

• decreased bronchodilation

• decreases HR and contractility

• increases GI activity

• pupil constriction

Genral senses

• visceral sensations

• touch

• temperature

• pain

• proprioception

special senses

• taste

• smell

• hearing

• equilibrium

• vising

static equilibrium

• uses gravity to determine position on a linear plane (like walking)

• part of the inner ear between the cochlea and semicircular canals

• made up of 2 sac like spaces the utricle and saccule

dynamic equilibrium

• three semicircular canals, each at right angles to each other

• sense head rotation by their different planes of orientation

disease of the ear

• otitis externa

• otitis interna

• ear mites

• aural hematoma

• guttural pouch mycosis

disease of the eye

• corneal ulcers

• conjunctivitis

• glaucoma

• cataracts

• ect

salivary glands

• parotid

• mandibular

• sublingual

• produces amylase, lipase (milk for young), lysozyme, bicarb(cattle)

layers of esophagus

• mucosa - line organ wall

• submucosa - connective tissue

• muscularis - smooth muscle layers

• serosa - serous membrane on outside of organ

swallowing

• starts as voluntary, turns involuntary

• reflex contraction of pharynx, movement of epiglitis to cover glottis, relaxation of esophagus to allow food bolus

• Peristalsis to move food to the stomach.

peristalsis

wave-like muscle contractions that move food through the digestive tract

vomiting (emesis)

• reflex controlled by the brainstem

• relaxation of pyloric sphincter

• reverse peristalsis

• relaxation of cardiac sphincter

• inspiratory movement against closed glottis and forceful abdominal contractions

• closed glottis prevents aspiration

• soft pallet directs injected out of mouth

parts of the stomach

• cardia - immediate opening

• fundus - blind pouch

• body - distensible middle part

• antrum - distal portion that grinds up food

• pylorus - muscular sphincter

glands that make enzymes to digest food

Exocrine glands in the pancreas and salivary glands.

parts of small intestine

duodenum - the first section of the small intestine, where most chemical digestion occurs.

Jejunum- the second section of the small intestine, responsible for nutrient absorption.

Ileum- the final section of the small intestine, where remaining nutrients are absorbed and bile salts are reclaimed.

layers of hollow organ

1. mucosa- epithelium in direct contact with contents

2. Submucosa- made of connective tissue contains blood vessels

3. muscular - smooth muscle layer responsible for peristalsis

4. serosa - visceral peritoneum outermost layer that provides protection

glands of the stomach

• mucous - secretes mucus to protect the stomach from acid

• parietal - secretes HCL - lower pH, kill microbes

• chief cell - secretes pepsiongen- digests proteins

• endocrine cell- secretes gastrin hormone stimulated acid and gastric motility

ruminant stomach

“foregut fermentor”

• reticulum - honeycomb- rumination

• rumen- “pile rug” fermentation, makes VFA

• omasum- book- absorb water

• abomasum- glands make digestive enzymes

carbohydrate digestion

• digested into monosaccharides, absorbed into the small intestine epithelium using secondary active transport

• enzymes- amylase, maltase, lactase, sucrase

• pancreas secretion and brush border enzymes

protein digestion

• digested into amino acids in stomach and small intestine, absorbed into the small intestine using secondary active transport like glucose

• enzymes pepsin (stomach) , luminal peptidases (pancreas)

lipid digestion

• stomach- emulsification into small droplets

• duodenum- lipids are hydrolyzed into 2 free fatty acids and 1 monoglyceride

• brush border- micelle travels to microvilli

• In epitherial cell- triglyceride is reassembled and packaged into chylomicrons for transport

• transported through lymph to vena cava then into circulation

large intestine

• ascending

• transcending

• descending

  function- recover water and electrolytes, store feces, ferment fiber

large intestine hind gut fermenter

• equine, rodents, rabbits, guinea pigs

• all have enlarged cecum

pancreas

• Exocrine gland function is important for digestion

• secretes

  • proteases, amylase, lipase

  • bicarbonate to neutralize stomach acid

  • travels through pancreatic duct

5 functions of the liver

• filter and detoxify substance from the GIT in the blood

• absorb and store vitamins, minerals, glucose from the GIT

• produces bile

• makes some blood proteins (albumin)

• glucose metabolism

hepatic portal system

system of veins that drain the intestine and deliver blood to the liver

hormones

hormones are controlled by feedback loops that can be negative (usuadreally) or positive

adrenal cortex hormones

1. Mineralocorticoid hormone Aldosterone - acts on kidneys to increase sodium reabsorption- results in water retention

2. Glucocorticoid- stress hormone/ cortisol - maintains blood pressure, energy glucose supply

3. sex hormone- aldosterone and estrogen

side effects of glucocorticoids

• PU/PD

• immunosuppression

• Altered WBC count

• delayed wound healing

• catabolism of proteins

• abortion

• hyperglycemia

• suppresses normal adrenal cortex secretions

pancreatic hormones

Insulin lowers blood glucose

Glucagon - raises blood glucose

blood

• connective tissue

• provides internal transport- oxygen, nutrients, waste, hormones, WBC, platelets

• regulates- body temp, tissue fluid reservoir, pH

• defends the body- WBC, platelets/clotting factors

plasma

fluid portion of blood

serum

fluid that is left after blood has clotted

blood volume

• about 6-9% of lean body weight

• fit muscular animals have greater blood volume

red blood cells

• erythrocytes

• carry oxygen bound to hemoglobin

white blood cells

• leukocytes

• some have granules and are named according to staining characteristics (granulocytes)

• others do not have granulocytes (agranulocytes)

• function in the immune response

platelets

• thrombocytes

• helps blood clot when vessels are damaged

erythropoiesis

• the production of red blood cells from the PPSC in bone marrow

• stimulated by erythropoietin, a hormone produced by the kidneys.

anemia

1. loss due to hemorrhage, parasitism

2. increased RBC destruction - hemolysis

3. Decreased RBC production - chronic disease- bone marrow suppression

platelet functions

1. Maintain vascular integrity - low platelets = petechia

2. Platelet plug formation to stop hemorrhage

3. Release clotting factors to convert fibrinogen to fibrin to stabilize the clot

clotting process

1. Immediate vasoconstricting to reduce hemorrhage

2. Platelet plug formation - plate adhesion followed by platelet aggregation

3. clot stabilization- platelets release clotting factors that initiate clotting cascade to turn fibrinogen into fibrin

5 kinds of white blood cells

• monocyte

• lymphocyte

• neutrophil

• eosinophil

• basophil

monocyte

large cell that engulfs and destroys foreign particles. Migrate in tissues to become macrophages

lymphocyte

smaller and are involved with immune responses / antibody production

3 types of granulocytes

• Neutrophil- phagocyte foreign invader (pale purple)

• basophils - involves in allergic reaction and inflammation (dark blue)

• eosinophils- allergies and parasitic infections (red)

lymphatic system includes

• bone

• lymph vessels

• lymph nodes

• spleen

• thymus

• lymphoid tissue

3 major function of lymphoid tissue

1. Return of extracellular fluid to blood, including waste

2. filtration and defense against infection

3. protein and lipid transportation

spleen function

1. Storage area for blood

2. part of a system of macrophages distributed throughout the liver and spleen that “clean up”

thymus

An organ in the lymphatic system where T cells mature, playing a crucial role in the immune response.

located cranial thoracic region

large in young animals

tonsils

found all regions of the body

are peripheral lymphoid tissue where mature lymphocytes live